diff --git a/Examples/BookingSystem.AspNetFramework.Tests/App.config b/Examples/BookingSystem.AspNetFramework.Tests/App.config
index 18291db0..40607753 100644
--- a/Examples/BookingSystem.AspNetFramework.Tests/App.config
+++ b/Examples/BookingSystem.AspNetFramework.Tests/App.config
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <!--
     Note: Add entries to the App.config file for configuration settings
     that apply only to the Test project.
@@ -14,81 +14,81 @@
   <runtime>
     <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
       <dependentAssembly>
-        <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-11.0.0.0" newVersion="11.0.0.0"/>
+        <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-11.0.0.0" newVersion="11.0.0.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-1.6.5135.21930" newVersion="1.6.5135.21930"/>
+        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-1.6.5135.21930" newVersion="1.6.5135.21930" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="Antlr3.Runtime" publicKeyToken="eb42632606e9261f" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-3.5.0.2" newVersion="3.5.0.2"/>
+        <assemblyIdentity name="Antlr3.Runtime" publicKeyToken="eb42632606e9261f" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-3.5.0.2" newVersion="3.5.0.2" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="Microsoft.Owin" publicKeyToken="31bf3856ad364e35" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0"/>
+        <assemblyIdentity name="Microsoft.Owin" publicKeyToken="31bf3856ad364e35" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="Microsoft.Owin.Security.OAuth" publicKeyToken="31bf3856ad364e35" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0"/>
+        <assemblyIdentity name="Microsoft.Owin.Security.OAuth" publicKeyToken="31bf3856ad364e35" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="Microsoft.Owin.Security" publicKeyToken="31bf3856ad364e35" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0"/>
+        <assemblyIdentity name="Microsoft.Owin.Security" publicKeyToken="31bf3856ad364e35" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="Microsoft.IdentityModel.Logging" publicKeyToken="31bf3856ad364e35" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-5.2.4.0" newVersion="5.2.4.0"/>
+        <assemblyIdentity name="Microsoft.IdentityModel.Logging" publicKeyToken="31bf3856ad364e35" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-5.2.4.0" newVersion="5.2.4.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="Microsoft.IdentityModel.Tokens" publicKeyToken="31bf3856ad364e35" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-5.2.4.0" newVersion="5.2.4.0"/>
+        <assemblyIdentity name="Microsoft.IdentityModel.Tokens" publicKeyToken="31bf3856ad364e35" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-5.2.4.0" newVersion="5.2.4.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="System.IdentityModel.Tokens.Jwt" publicKeyToken="31bf3856ad364e35" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-5.2.4.0" newVersion="5.2.4.0"/>
+        <assemblyIdentity name="System.IdentityModel.Tokens.Jwt" publicKeyToken="31bf3856ad364e35" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-5.2.4.0" newVersion="5.2.4.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="System.Buffers" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-4.0.3.0" newVersion="4.0.3.0"/>
+        <assemblyIdentity name="System.Buffers" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.3.0" newVersion="4.0.3.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="Microsoft.Extensions.DependencyInjection.Abstractions" publicKeyToken="adb9793829ddae60" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-3.0.0.0" newVersion="3.0.0.0"/>
+        <assemblyIdentity name="Microsoft.Extensions.DependencyInjection.Abstractions" publicKeyToken="adb9793829ddae60" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="Microsoft.IdentityModel.Protocols.OpenIdConnect" publicKeyToken="31bf3856ad364e35" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-5.2.1.0" newVersion="5.2.1.0"/>
+        <assemblyIdentity name="Microsoft.IdentityModel.Protocols.OpenIdConnect" publicKeyToken="31bf3856ad364e35" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-5.2.1.0" newVersion="5.2.1.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="Microsoft.IdentityModel.Protocols" publicKeyToken="31bf3856ad364e35" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-5.2.1.0" newVersion="5.2.1.0"/>
+        <assemblyIdentity name="Microsoft.IdentityModel.Protocols" publicKeyToken="31bf3856ad364e35" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-5.2.1.0" newVersion="5.2.1.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="System.Security.Cryptography.Cng" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-4.3.1.0" newVersion="4.3.1.0"/>
+        <assemblyIdentity name="System.Security.Cryptography.Cng" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.3.1.0" newVersion="4.3.1.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="System.Memory" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-4.0.1.1" newVersion="4.0.1.1"/>
+        <assemblyIdentity name="System.Memory" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.1.1" newVersion="4.0.1.1" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="System.Runtime.CompilerServices.Unsafe" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-4.0.4.1" newVersion="4.0.4.1"/>
+        <assemblyIdentity name="System.Runtime.CompilerServices.Unsafe" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.4.1" newVersion="4.0.4.1" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="Schema.NET" publicKeyToken="fc5550082a9c642c" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-7.0.1.0" newVersion="7.0.1.0"/>
+        <assemblyIdentity name="Schema.NET" publicKeyToken="fc5550082a9c642c" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-7.0.1.0" newVersion="7.0.1.0" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="System.Threading.Tasks.Extensions" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-4.2.0.1" newVersion="4.2.0.1"/>
+        <assemblyIdentity name="System.Threading.Tasks.Extensions" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.2.0.1" newVersion="4.2.0.1" />
       </dependentAssembly>
       <dependentAssembly>
-        <assemblyIdentity name="System.ComponentModel.Annotations" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-4.2.1.0" newVersion="4.2.1.0"/>
+        <assemblyIdentity name="System.ComponentModel.Annotations" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.2.1.0" newVersion="4.2.1.0" />
       </dependentAssembly>
     </assemblyBinding>
   </runtime>
-<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.2"/></startup></configuration>
+<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.2" /></startup></configuration>
diff --git a/Examples/BookingSystem.AspNetFramework.Tests/BookingSystem.AspNetFramework.Tests.csproj b/Examples/BookingSystem.AspNetFramework.Tests/BookingSystem.AspNetFramework.Tests.csproj
index 3fa756ef..1bd7a5ea 100644
--- a/Examples/BookingSystem.AspNetFramework.Tests/BookingSystem.AspNetFramework.Tests.csproj
+++ b/Examples/BookingSystem.AspNetFramework.Tests/BookingSystem.AspNetFramework.Tests.csproj
@@ -36,6 +36,10 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="AsyncKeyedLock, Version=6.2.4.0, Culture=neutral, PublicKeyToken=c6dde91429ba0f2f, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\AsyncKeyedLock.6.2.4\lib\netstandard2.0\AsyncKeyedLock.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
     <Reference Include="Microsoft.CSharp" />
     <Reference Include="Microsoft.VisualStudio.TestPlatform.TestFramework">
       <HintPath>..\..\packages\MSTest.TestFramework.1.2.0\lib\net45\Microsoft.VisualStudio.TestPlatform.TestFramework.dll</HintPath>
@@ -48,6 +52,12 @@
     <Reference Include="System.Configuration" />
     <Reference Include="System.Core" />
     <Reference Include="System.Data" />
+    <Reference Include="System.Runtime.CompilerServices.Unsafe, Version=4.0.4.1, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\System.Runtime.CompilerServices.Unsafe.4.5.3\lib\net461\System.Runtime.CompilerServices.Unsafe.dll</HintPath>
+    </Reference>
+    <Reference Include="System.Threading.Tasks.Extensions, Version=4.2.0.1, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\System.Threading.Tasks.Extensions.4.5.4\lib\net461\System.Threading.Tasks.Extensions.dll</HintPath>
+    </Reference>
     <Reference Include="System.Web" />
     <Reference Include="System.Web.ApplicationServices" />
     <Reference Include="System.Web.Extensions" />
@@ -132,4 +142,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
\ No newline at end of file
+</Project>
diff --git a/Examples/BookingSystem.AspNetFramework.Tests/packages.config b/Examples/BookingSystem.AspNetFramework.Tests/packages.config
index 69c97d6d..ae3cf376 100644
--- a/Examples/BookingSystem.AspNetFramework.Tests/packages.config
+++ b/Examples/BookingSystem.AspNetFramework.Tests/packages.config
@@ -1,13 +1,16 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="Microsoft.AspNet.Mvc" version="5.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.Razor" version="3.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.WebApi.Client" version="5.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.WebApi.Core" version="5.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.WebApi.WebHost" version="5.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.WebPages" version="3.2.7" targetFramework="net461" />
-  <package id="Microsoft.Web.Infrastructure" version="1.0.0.0" targetFramework="net461" />
-  <package id="MSTest.TestAdapter" version="1.2.0" targetFramework="net461" />
-  <package id="MSTest.TestFramework" version="1.2.0" targetFramework="net461" />
-  <package id="Newtonsoft.Json" version="11.0.1" targetFramework="net461" />
-</packages>
\ No newline at end of file
+  <package id="AsyncKeyedLock" version="6.2.4" targetFramework="net462" />
+  <package id="Microsoft.AspNet.Mvc" version="5.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.Razor" version="3.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.WebApi.Client" version="5.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.WebApi.Core" version="5.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.WebApi.WebHost" version="5.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.WebPages" version="3.2.7" targetFramework="net462" />
+  <package id="Microsoft.Web.Infrastructure" version="1.0.0.0" targetFramework="net462" />
+  <package id="MSTest.TestAdapter" version="1.2.0" targetFramework="net462" />
+  <package id="MSTest.TestFramework" version="1.2.0" targetFramework="net462" />
+  <package id="Newtonsoft.Json" version="11.0.1" targetFramework="net462" />
+  <package id="System.Runtime.CompilerServices.Unsafe" version="4.5.3" targetFramework="net462" />
+  <package id="System.Threading.Tasks.Extensions" version="4.5.4" targetFramework="net462" />
+</packages>
diff --git a/Examples/BookingSystem.AspNetFramework/BookingSystem.AspNetFramework.csproj b/Examples/BookingSystem.AspNetFramework/BookingSystem.AspNetFramework.csproj
index c89ec8a1..61444d42 100644
--- a/Examples/BookingSystem.AspNetFramework/BookingSystem.AspNetFramework.csproj
+++ b/Examples/BookingSystem.AspNetFramework/BookingSystem.AspNetFramework.csproj
@@ -47,6 +47,10 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="AsyncKeyedLock, Version=6.2.4.0, Culture=neutral, PublicKeyToken=c6dde91429ba0f2f, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\AsyncKeyedLock.6.2.4\lib\netstandard2.0\AsyncKeyedLock.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
     <Reference Include="Bogus, Version=33.0.2.0, Culture=neutral, PublicKeyToken=fa1bb3f3f218129a, processorArchitecture=MSIL">
       <HintPath>..\..\packages\Bogus.33.0.2\lib\net40\Bogus.dll</HintPath>
     </Reference>
@@ -540,4 +544,4 @@
   </Target>
   <Target Name="AfterBuild">
   </Target> -->
-</Project>
\ No newline at end of file
+</Project>
diff --git a/Examples/BookingSystem.AspNetFramework/Web.config b/Examples/BookingSystem.AspNetFramework/Web.config
index 767c1399..a87e8459 100644
--- a/Examples/BookingSystem.AspNetFramework/Web.config
+++ b/Examples/BookingSystem.AspNetFramework/Web.config
@@ -1,4 +1,4 @@
-<?xml version="1.0"?>
+<?xml version="1.0" encoding="utf-8"?>
 <!--
   For more information on how to configure your ASP.NET application, please visit
   https://go.microsoft.com/fwlink/?LinkId=301879
@@ -40,7 +40,7 @@
 				<add assembly="System.ComponentModel.Composition, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
 			</assemblies>
 		</compilation>
-		<httpRuntime targetFramework="4.6.1" />
+		<httpRuntime targetFramework="4.6.2" />
 	</system.web>
 	<system.webServer>
 		<modules>
@@ -385,4 +385,4 @@
 			<compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
 		</compilers>
 	</system.codedom>
-</configuration>
\ No newline at end of file
+</configuration>
diff --git a/Examples/BookingSystem.AspNetFramework/packages.config b/Examples/BookingSystem.AspNetFramework/packages.config
index 38b069d0..b7c0d74e 100644
--- a/Examples/BookingSystem.AspNetFramework/packages.config
+++ b/Examples/BookingSystem.AspNetFramework/packages.config
@@ -1,130 +1,131 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="Antlr" version="3.5.0.2" targetFramework="net461" />
-  <package id="Bogus" version="33.0.2" targetFramework="net461" />
-  <package id="bootstrap" version="3.4.1" targetFramework="net461" />
-  <package id="EntityFramework" version="6.2.0" targetFramework="net461" />
-  <package id="IdentityModel" version="3.10.10" targetFramework="net461" />
-  <package id="IdentityServer4" version="2.5.3" targetFramework="net461" />
-  <package id="IdentityServer4.Storage" version="2.5.3" targetFramework="net461" />
-  <package id="jQuery" version="3.3.1" targetFramework="net461" />
-  <package id="jQuery.Validation" version="1.17.0" targetFramework="net461" />
-  <package id="Microsoft.AspNet.Identity.Core" version="2.2.2" targetFramework="net461" />
-  <package id="Microsoft.AspNet.Identity.EntityFramework" version="2.2.2" targetFramework="net461" />
-  <package id="Microsoft.AspNet.Identity.Owin" version="2.2.2" targetFramework="net461" />
-  <package id="Microsoft.AspNet.Mvc" version="5.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.Razor" version="3.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.Web.Optimization" version="1.1.3" targetFramework="net461" />
-  <package id="Microsoft.AspNet.WebApi" version="5.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.WebApi.Client" version="5.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.WebApi.Core" version="5.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.WebApi.HelpPage" version="5.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.WebApi.Owin" version="5.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.WebApi.WebHost" version="5.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNet.WebPages" version="3.2.7" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Authentication" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Authentication.Abstractions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Authentication.Cookies" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Authentication.Core" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Authentication.OAuth" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Authentication.OpenIdConnect" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Authorization" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Cors" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Cryptography.Internal" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.DataProtection" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.DataProtection.Abstractions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Hosting.Abstractions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Hosting.Server.Abstractions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Http" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Http.Abstractions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Http.Extensions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.Http.Features" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.AspNetCore.WebUtilities" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Bcl.AsyncInterfaces" version="1.1.0" targetFramework="net461" />
-  <package id="Microsoft.CodeDom.Providers.DotNetCompilerPlatform" version="2.0.0" targetFramework="net461" />
-  <package id="Microsoft.CSharp" version="4.5.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Caching.Abstractions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Caching.Memory" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Configuration" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Configuration.Abstractions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Configuration.Binder" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.DependencyInjection" version="3.0.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.DependencyInjection.Abstractions" version="3.0.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.FileProviders.Abstractions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Hosting.Abstractions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Http" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Logging" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Logging.Abstractions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.ObjectPool" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Options" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Options.ConfigurationExtensions" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.Primitives" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Extensions.WebEncoders" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.IdentityModel.JsonWebTokens" version="5.2.4" targetFramework="net461" />
-  <package id="Microsoft.IdentityModel.Logging" version="5.2.4" targetFramework="net461" />
-  <package id="Microsoft.IdentityModel.Protocols" version="5.2.1" targetFramework="net461" />
-  <package id="Microsoft.IdentityModel.Protocols.OpenIdConnect" version="5.2.1" targetFramework="net461" />
-  <package id="Microsoft.IdentityModel.Tokens" version="5.2.4" targetFramework="net461" />
-  <package id="Microsoft.jQuery.Unobtrusive.Validation" version="3.2.11" targetFramework="net461" />
-  <package id="Microsoft.Net.Http.Headers" version="2.1.0" targetFramework="net461" />
-  <package id="Microsoft.Owin" version="4.0.0" targetFramework="net461" />
-  <package id="Microsoft.Owin.Host.SystemWeb" version="4.0.0" targetFramework="net461" />
-  <package id="Microsoft.Owin.Security" version="4.0.0" targetFramework="net461" />
-  <package id="Microsoft.Owin.Security.Cookies" version="4.0.0" targetFramework="net461" />
-  <package id="Microsoft.Owin.Security.Facebook" version="4.0.0" targetFramework="net461" />
-  <package id="Microsoft.Owin.Security.Google" version="4.0.0" targetFramework="net461" />
-  <package id="Microsoft.Owin.Security.MicrosoftAccount" version="4.0.0" targetFramework="net461" />
-  <package id="Microsoft.Owin.Security.OAuth" version="4.0.0" targetFramework="net461" />
-  <package id="Microsoft.Owin.Security.Twitter" version="4.0.0" targetFramework="net461" />
-  <package id="Microsoft.Web.Infrastructure" version="1.0.0.0" targetFramework="net461" />
-  <package id="Microsoft.Win32.Registry" version="4.5.0" targetFramework="net461" />
-  <package id="Modernizr" version="2.8.3" targetFramework="net461" />
-  <package id="Newtonsoft.Json" version="12.0.3" targetFramework="net461" />
-  <package id="OpenActive.DatasetSite.NET" version="6.0.2" targetFramework="net461" />
-  <package id="OpenActive.NET" version="15.2.17" targetFramework="net461" />
-  <package id="Owin" version="1.0" targetFramework="net461" />
-  <package id="Schema.NET" version="7.0.1" targetFramework="net461" />
-  <package id="ServiceStack.Common" version="5.10.4" targetFramework="net461" />
-  <package id="ServiceStack.Common.Core" version="5.11.0" targetFramework="net461" />
-  <package id="ServiceStack.Interfaces" version="5.10.4" targetFramework="net461" />
-  <package id="ServiceStack.Interfaces.Core" version="5.11.0" targetFramework="net461" />
-  <package id="ServiceStack.OrmLite" version="5.10.4" targetFramework="net461" />
-  <package id="ServiceStack.OrmLite.Core" version="5.11.0" targetFramework="net461" />
-  <package id="ServiceStack.OrmLite.Sqlite.Core" version="5.11.0" targetFramework="net461" />
-  <package id="ServiceStack.Text" version="5.10.4" targetFramework="net461" />
-  <package id="ServiceStack.Text.Core" version="5.11.0" targetFramework="net461" />
-  <package id="Stub.System.Data.SQLite.Core.NetFramework" version="1.0.113.3" targetFramework="net461" />
-  <package id="Stubble.Core" version="1.9.3" targetFramework="net461" />
-  <package id="Stubble.Extensions.JsonNet" version="1.2.3" targetFramework="net461" />
-  <package id="Stubble.Extensions.JsonNet.Net45" version="1.3.3" targetFramework="net461" />
-  <package id="System.Buffers" version="4.5.1" targetFramework="net461" />
-  <package id="System.Collections.Immutable" version="1.5.0" targetFramework="net461" />
-  <package id="System.Collections.NonGeneric" version="4.3.0" targetFramework="net461" />
-  <package id="System.ComponentModel.Annotations" version="5.0.0" targetFramework="net461" />
-  <package id="System.ComponentModel.Primitives" version="4.3.0" targetFramework="net461" />
-  <package id="System.Data.Common" version="4.3.0" targetFramework="net461" />
-  <package id="System.Data.SQLite.Core" version="1.0.113.7" targetFramework="net461" />
-  <package id="System.Dynamic.Runtime" version="4.3.0" targetFramework="net461" />
-  <package id="System.IdentityModel.Tokens.Jwt" version="5.2.4" targetFramework="net461" />
-  <package id="System.Memory" version="4.5.4" targetFramework="net461" />
-  <package id="System.Net.NetworkInformation" version="4.3.0" targetFramework="net461" />
-  <package id="System.Net.Requests" version="4.3.0" targetFramework="net461" />
-  <package id="System.Numerics.Vectors" version="4.5.0" targetFramework="net461" />
-  <package id="System.Reflection.Emit" version="4.3.0" targetFramework="net461" />
-  <package id="System.Reflection.Emit.Lightweight" version="4.3.0" targetFramework="net461" />
-  <package id="System.Reflection.TypeExtensions" version="4.5.0" targetFramework="net461" />
-  <package id="System.Runtime" version="4.3.1" targetFramework="net461" requireReinstallation="true" />
-  <package id="System.Runtime.CompilerServices.Unsafe" version="4.5.3" targetFramework="net461" />
-  <package id="System.Runtime.Serialization.Primitives" version="4.3.0" targetFramework="net461" />
-  <package id="System.Security.AccessControl" version="4.5.0" targetFramework="net461" />
-  <package id="System.Security.Cryptography.Cng" version="4.5.0" targetFramework="net461" requireReinstallation="true" />
-  <package id="System.Security.Cryptography.Xml" version="4.5.0" targetFramework="net461" />
-  <package id="System.Security.Permissions" version="4.5.0" targetFramework="net461" />
-  <package id="System.Security.Principal.Windows" version="4.5.0" targetFramework="net461" />
-  <package id="System.Text.Encodings.Web" version="4.5.0" targetFramework="net461" />
-  <package id="System.Threading.Tasks.Extensions" version="4.5.4" targetFramework="net461" />
-  <package id="System.ValueTuple" version="4.5.0" targetFramework="net461" />
-  <package id="System.Xml.XmlDocument" version="4.3.0" targetFramework="net461" />
-  <package id="UriTemplate.Core" version="1.0.2" targetFramework="net461" />
-  <package id="WebGrease" version="1.6.0" targetFramework="net461" />
+  <package id="Antlr" version="3.5.0.2" targetFramework="net462" />
+  <package id="AsyncKeyedLock" version="6.0.5" targetFramework="net462" />
+  <package id="Bogus" version="33.0.2" targetFramework="net462" />
+  <package id="bootstrap" version="3.4.1" targetFramework="net462" />
+  <package id="EntityFramework" version="6.2.0" targetFramework="net462" />
+  <package id="IdentityModel" version="3.10.10" targetFramework="net462" />
+  <package id="IdentityServer4" version="2.5.3" targetFramework="net462" />
+  <package id="IdentityServer4.Storage" version="2.5.3" targetFramework="net462" />
+  <package id="jQuery" version="3.3.1" targetFramework="net462" />
+  <package id="jQuery.Validation" version="1.17.0" targetFramework="net462" />
+  <package id="Microsoft.AspNet.Identity.Core" version="2.2.2" targetFramework="net462" />
+  <package id="Microsoft.AspNet.Identity.EntityFramework" version="2.2.2" targetFramework="net462" />
+  <package id="Microsoft.AspNet.Identity.Owin" version="2.2.2" targetFramework="net462" />
+  <package id="Microsoft.AspNet.Mvc" version="5.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.Razor" version="3.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.Web.Optimization" version="1.1.3" targetFramework="net462" />
+  <package id="Microsoft.AspNet.WebApi" version="5.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.WebApi.Client" version="5.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.WebApi.Core" version="5.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.WebApi.HelpPage" version="5.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.WebApi.Owin" version="5.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.WebApi.WebHost" version="5.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNet.WebPages" version="3.2.7" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Authentication" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Authentication.Abstractions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Authentication.Cookies" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Authentication.Core" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Authentication.OAuth" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Authentication.OpenIdConnect" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Authorization" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Cors" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Cryptography.Internal" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.DataProtection" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.DataProtection.Abstractions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Hosting.Abstractions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Hosting.Server.Abstractions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Http" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Http.Abstractions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Http.Extensions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.Http.Features" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.AspNetCore.WebUtilities" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Bcl.AsyncInterfaces" version="1.1.0" targetFramework="net462" />
+  <package id="Microsoft.CodeDom.Providers.DotNetCompilerPlatform" version="2.0.0" targetFramework="net462" />
+  <package id="Microsoft.CSharp" version="4.5.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Caching.Abstractions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Caching.Memory" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Configuration" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Configuration.Abstractions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Configuration.Binder" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.DependencyInjection" version="3.0.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.DependencyInjection.Abstractions" version="3.0.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.FileProviders.Abstractions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Hosting.Abstractions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Http" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Logging" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Logging.Abstractions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.ObjectPool" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Options" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Options.ConfigurationExtensions" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.Primitives" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Extensions.WebEncoders" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.IdentityModel.JsonWebTokens" version="5.2.4" targetFramework="net462" />
+  <package id="Microsoft.IdentityModel.Logging" version="5.2.4" targetFramework="net462" />
+  <package id="Microsoft.IdentityModel.Protocols" version="5.2.1" targetFramework="net462" />
+  <package id="Microsoft.IdentityModel.Protocols.OpenIdConnect" version="5.2.1" targetFramework="net462" />
+  <package id="Microsoft.IdentityModel.Tokens" version="5.2.4" targetFramework="net462" />
+  <package id="Microsoft.jQuery.Unobtrusive.Validation" version="3.2.11" targetFramework="net462" />
+  <package id="Microsoft.Net.Http.Headers" version="2.1.0" targetFramework="net462" />
+  <package id="Microsoft.Owin" version="4.0.0" targetFramework="net462" />
+  <package id="Microsoft.Owin.Host.SystemWeb" version="4.0.0" targetFramework="net462" />
+  <package id="Microsoft.Owin.Security" version="4.0.0" targetFramework="net462" />
+  <package id="Microsoft.Owin.Security.Cookies" version="4.0.0" targetFramework="net462" />
+  <package id="Microsoft.Owin.Security.Facebook" version="4.0.0" targetFramework="net462" />
+  <package id="Microsoft.Owin.Security.Google" version="4.0.0" targetFramework="net462" />
+  <package id="Microsoft.Owin.Security.MicrosoftAccount" version="4.0.0" targetFramework="net462" />
+  <package id="Microsoft.Owin.Security.OAuth" version="4.0.0" targetFramework="net462" />
+  <package id="Microsoft.Owin.Security.Twitter" version="4.0.0" targetFramework="net462" />
+  <package id="Microsoft.Web.Infrastructure" version="1.0.0.0" targetFramework="net462" />
+  <package id="Microsoft.Win32.Registry" version="4.5.0" targetFramework="net462" />
+  <package id="Modernizr" version="2.8.3" targetFramework="net462" />
+  <package id="Newtonsoft.Json" version="12.0.3" targetFramework="net462" />
+  <package id="OpenActive.DatasetSite.NET" version="6.0.2" targetFramework="net462" />
+  <package id="OpenActive.NET" version="15.2.17" targetFramework="net462" />
+  <package id="Owin" version="1.0" targetFramework="net462" />
+  <package id="Schema.NET" version="7.0.1" targetFramework="net462" />
+  <package id="ServiceStack.Common" version="5.10.4" targetFramework="net462" />
+  <package id="ServiceStack.Common.Core" version="5.11.0" targetFramework="net462" />
+  <package id="ServiceStack.Interfaces" version="5.10.4" targetFramework="net462" />
+  <package id="ServiceStack.Interfaces.Core" version="5.11.0" targetFramework="net462" />
+  <package id="ServiceStack.OrmLite" version="5.10.4" targetFramework="net462" />
+  <package id="ServiceStack.OrmLite.Core" version="5.11.0" targetFramework="net462" />
+  <package id="ServiceStack.OrmLite.Sqlite.Core" version="5.11.0" targetFramework="net462" />
+  <package id="ServiceStack.Text" version="5.10.4" targetFramework="net462" />
+  <package id="ServiceStack.Text.Core" version="5.11.0" targetFramework="net462" />
+  <package id="Stub.System.Data.SQLite.Core.NetFramework" version="1.0.113.3" targetFramework="net462" />
+  <package id="Stubble.Core" version="1.9.3" targetFramework="net462" />
+  <package id="Stubble.Extensions.JsonNet" version="1.2.3" targetFramework="net462" />
+  <package id="Stubble.Extensions.JsonNet.Net45" version="1.3.3" targetFramework="net462" />
+  <package id="System.Buffers" version="4.5.1" targetFramework="net462" />
+  <package id="System.Collections.Immutable" version="1.5.0" targetFramework="net462" />
+  <package id="System.Collections.NonGeneric" version="4.3.0" targetFramework="net462" />
+  <package id="System.ComponentModel.Annotations" version="5.0.0" targetFramework="net462" />
+  <package id="System.ComponentModel.Primitives" version="4.3.0" targetFramework="net462" />
+  <package id="System.Data.Common" version="4.3.0" targetFramework="net462" />
+  <package id="System.Data.SQLite.Core" version="1.0.113.7" targetFramework="net462" />
+  <package id="System.Dynamic.Runtime" version="4.3.0" targetFramework="net462" />
+  <package id="System.IdentityModel.Tokens.Jwt" version="5.2.4" targetFramework="net462" />
+  <package id="System.Memory" version="4.5.4" targetFramework="net462" />
+  <package id="System.Net.NetworkInformation" version="4.3.0" targetFramework="net462" />
+  <package id="System.Net.Requests" version="4.3.0" targetFramework="net462" />
+  <package id="System.Numerics.Vectors" version="4.5.0" targetFramework="net462" />
+  <package id="System.Reflection.Emit" version="4.3.0" targetFramework="net462" />
+  <package id="System.Reflection.Emit.Lightweight" version="4.3.0" targetFramework="net462" />
+  <package id="System.Reflection.TypeExtensions" version="4.5.0" targetFramework="net462" />
+  <package id="System.Runtime" version="4.3.1" targetFramework="net462" requireReinstallation="true" />
+  <package id="System.Runtime.CompilerServices.Unsafe" version="4.5.3" targetFramework="net462" />
+  <package id="System.Runtime.Serialization.Primitives" version="4.3.0" targetFramework="net462" />
+  <package id="System.Security.AccessControl" version="4.5.0" targetFramework="net462" />
+  <package id="System.Security.Cryptography.Cng" version="4.5.0" targetFramework="net462" requireReinstallation="true" />
+  <package id="System.Security.Cryptography.Xml" version="4.5.0" targetFramework="net462" />
+  <package id="System.Security.Permissions" version="4.5.0" targetFramework="net462" />
+  <package id="System.Security.Principal.Windows" version="4.5.0" targetFramework="net462" />
+  <package id="System.Text.Encodings.Web" version="4.5.0" targetFramework="net462" />
+  <package id="System.Threading.Tasks.Extensions" version="4.5.4" targetFramework="net462" />
+  <package id="System.ValueTuple" version="4.5.0" targetFramework="net462" />
+  <package id="System.Xml.XmlDocument" version="4.3.0" targetFramework="net462" />
+  <package id="UriTemplate.Core" version="1.0.2" targetFramework="net462" />
+  <package id="WebGrease" version="1.6.0" targetFramework="net462" />
 </packages>
\ No newline at end of file
diff --git a/OpenActive.Server.NET/CustomBookingEngine/CustomBookingEngine.cs b/OpenActive.Server.NET/CustomBookingEngine/CustomBookingEngine.cs
index ff1fb6d6..3caa3d25 100644
--- a/OpenActive.Server.NET/CustomBookingEngine/CustomBookingEngine.cs
+++ b/OpenActive.Server.NET/CustomBookingEngine/CustomBookingEngine.cs
@@ -3,6 +3,7 @@
 using System.Linq;
 using System.Net;
 using System.Threading.Tasks;
+using AsyncKeyedLock;
 using OpenActive.DatasetSite.NET;
 using OpenActive.NET;
 using OpenActive.NET.Rpde.Version1;
@@ -129,7 +130,11 @@ public CustomBookingEngine(BookingEngineSettings settings, Uri openBookingAPIBas
         private Uri openDataFeedBaseUrl;
         private Dictionary<string, List<IBookablePairIdTemplate>> idConfigurationLookup;
         private Dictionary<OpportunityType, IBookablePairIdTemplate> feedAssignedTemplates;
-        private static readonly AsyncDuplicateLock asyncDuplicateLock = new AsyncDuplicateLock();
+        private static readonly AsyncKeyedLocker<string> asyncKeyedLock = new AsyncKeyedLocker<string>(o =>
+        {
+            o.PoolSize = 20;
+            o.PoolInitialFill = 1;
+        });
 
         protected Dictionary<OpportunityType, IBookablePairIdTemplate> OpportunityTemplateLookup { get; }
 
@@ -403,7 +408,7 @@ private async Task<ResponseContent> ProcessCheckpoint(string clientId, Uri selle
                 throw new OpenBookingException(new UnexpectedOrderTypeError(), "OrderQuote is required for C1 and C2");
             }
             var (orderId, sellerIdComponents, seller, customerAccountIdComponents) = await ConstructIdsFromRequest(clientId, sellerId, customerAccountId, uuidString, orderType);
-            using (await asyncDuplicateLock.LockAsync(GetParallelLockKey(orderId)))
+            using (await asyncKeyedLock.LockAsync(GetParallelLockKey(orderId)).ConfigureAwait(false))
             {
                 var orderResponse = await ProcessFlowRequest(ValidateFlowRequest<OrderQuote>(orderId, sellerIdComponents, seller, customerAccountIdComponents, flowStage, orderQuote), orderQuote);
 
@@ -420,7 +425,7 @@ public async Task<ResponseContent> ProcessOrderCreationB(string clientId, Uri se
                 throw new OpenBookingException(new UnexpectedOrderTypeError(), "Order is required for B");
             }
             var (orderId, sellerIdComponents, seller, customerAccountIdComponents) = await ConstructIdsFromRequest(clientId, sellerId, customerAccountId, uuidString, OrderType.Order);
-            using (await asyncDuplicateLock.LockAsync(GetParallelLockKey(orderId)))
+            using (await asyncKeyedLock.LockAsync(GetParallelLockKey(orderId)).ConfigureAwait(false))
             {
                 // Attempt to use idempotency cache if it exists
                 var cachedResponse = await GetResponseFromIdempotencyStoreIfExists(settings, orderId, orderJson);
@@ -445,7 +450,7 @@ public async Task<ResponseContent> ProcessOrderProposalCreationP(string clientId
                 throw new OpenBookingException(new UnexpectedOrderTypeError(), "OrderProposal is required for P");
             }
             var (orderId, sellerIdComponents, seller, customerAccountIdComponents) = await ConstructIdsFromRequest(clientId, sellerId, customerAccountId, uuidString, OrderType.OrderProposal);
-            using (await asyncDuplicateLock.LockAsync(GetParallelLockKey(orderId)))
+            using (await asyncKeyedLock.LockAsync(GetParallelLockKey(orderId)).ConfigureAwait(false))
             {
                 // Attempt to use idempotency cache if it exists
                 var cachedResponse = await GetResponseFromIdempotencyStoreIfExists(settings, orderId, orderJson);
@@ -515,7 +520,7 @@ private SimpleIdComponents GetCustomerAccountIdComponentsFromApiKey(Uri customer
         public async Task<ResponseContent> DeleteOrder(string clientId, Uri sellerId, string uuidString, Uri customerAccountId = null)
         {
             var orderId = new OrderIdComponents { ClientId = clientId, OrderType = OrderType.Order, uuid = ConvertToGuid(uuidString) };
-            using (await asyncDuplicateLock.LockAsync(GetParallelLockKey(orderId)))
+            using (await asyncKeyedLock.LockAsync(GetParallelLockKey(orderId)).ConfigureAwait(false))
             {
                 var result = await ProcessOrderDeletion(orderId, GetSimpleIdComponentsFromApiKey(sellerId), GetCustomerAccountIdComponentsFromApiKey(customerAccountId));
                 switch (result)
@@ -535,7 +540,7 @@ public async Task<ResponseContent> DeleteOrder(string clientId, Uri sellerId, st
         public async Task<ResponseContent> DeleteOrderQuote(string clientId, Uri sellerId, string uuidString, Uri customerAccountId = null)
         {
             var orderId = new OrderIdComponents { ClientId = clientId, OrderType = OrderType.OrderQuote, uuid = ConvertToGuid(uuidString) };
-            using (await asyncDuplicateLock.LockAsync(GetParallelLockKey(orderId)))
+            using (await asyncKeyedLock.LockAsync(GetParallelLockKey(orderId)).ConfigureAwait(false))
             {
                 await ProcessOrderQuoteDeletion(orderId, GetSimpleIdComponentsFromApiKey(sellerId), GetCustomerAccountIdComponentsFromApiKey(customerAccountId));
                 return ResponseContent.OpenBookingNoContentResponse();
@@ -547,7 +552,7 @@ public async Task<ResponseContent> DeleteOrderQuote(string clientId, Uri sellerI
         public async Task<ResponseContent> ProcessOrderUpdate(string clientId, Uri sellerId, string uuidString, string orderJson, Uri customerAccountId = null)
         {
             var orderId = new OrderIdComponents { ClientId = clientId, OrderType = OrderType.Order, uuid = ConvertToGuid(uuidString) };
-            using (await asyncDuplicateLock.LockAsync(GetParallelLockKey(orderId)))
+            using (await asyncKeyedLock.LockAsync(GetParallelLockKey(orderId)).ConfigureAwait(false))
             {
                 Order order = OpenActiveSerializer.Deserialize<Order>(orderJson);
                 SimpleIdComponents sellerIdComponents = GetSimpleIdComponentsFromApiKey(sellerId);
@@ -608,7 +613,7 @@ public async Task<ResponseContent> ProcessOrderUpdate(string clientId, Uri selle
         public async Task<ResponseContent> ProcessOrderProposalUpdate(string clientId, Uri sellerId, string uuidString, string orderProposalJson, Uri customerAccountId = null)
         {
             var orderId = new OrderIdComponents { ClientId = clientId, OrderType = OrderType.OrderProposal, uuid = ConvertToGuid(uuidString) };
-            using (await asyncDuplicateLock.LockAsync(GetParallelLockKey(orderId)))
+            using (await asyncKeyedLock.LockAsync(GetParallelLockKey(orderId)).ConfigureAwait(false))
             {
                 OrderProposal orderProposal = OpenActiveSerializer.Deserialize<OrderProposal>(orderProposalJson);
                 SimpleIdComponents sellerIdComponents = GetSimpleIdComponentsFromApiKey(sellerId);
diff --git a/OpenActive.Server.NET/OpenActive.Server.NET.csproj b/OpenActive.Server.NET/OpenActive.Server.NET.csproj
index 1dd2ab94..58f49632 100644
--- a/OpenActive.Server.NET/OpenActive.Server.NET.csproj
+++ b/OpenActive.Server.NET/OpenActive.Server.NET.csproj
@@ -26,6 +26,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="AsyncKeyedLock" Version="6.2.4" />
     <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="2.9.7">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
diff --git a/OpenActive.Server.NET/OpenBookingHelper/Async/AsyncDuplicateLock.cs b/OpenActive.Server.NET/OpenBookingHelper/Async/AsyncDuplicateLock.cs
deleted file mode 100644
index 37575f7a..00000000
--- a/OpenActive.Server.NET/OpenBookingHelper/Async/AsyncDuplicateLock.cs
+++ /dev/null
@@ -1,73 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
-
-namespace OpenActive.Server.NET.OpenBookingHelper
-{
-    public sealed class AsyncDuplicateLock
-    {
-        private sealed class RefCounted<T>
-        {
-            public RefCounted(T value)
-            {
-                RefCount = 1;
-                Value = value;
-            }
-
-            public int RefCount { get; set; }
-            public T Value { get; private set; }
-        }
-
-        private static readonly Dictionary<object, RefCounted<SemaphoreSlim>> SemaphoreSlims
-                              = new Dictionary<object, RefCounted<SemaphoreSlim>>();
-
-        private SemaphoreSlim GetOrCreate(object key)
-        {
-            RefCounted<SemaphoreSlim> item;
-            lock (SemaphoreSlims)
-            {
-                if (SemaphoreSlims.TryGetValue(key, out item))
-                {
-                    ++item.RefCount;
-                }
-                else
-                {
-                    item = new RefCounted<SemaphoreSlim>(new SemaphoreSlim(1, 1));
-                    SemaphoreSlims[key] = item;
-                }
-            }
-            return item.Value;
-        }
-
-        public IDisposable Lock(object key)
-        {
-            GetOrCreate(key).Wait();
-            return new Releaser { Key = key };
-        }
-
-        public async Task<IDisposable> LockAsync(object key)
-        {
-            await GetOrCreate(key).WaitAsync().ConfigureAwait(false);
-            return new Releaser { Key = key };
-        }
-
-        private sealed class Releaser : IDisposable
-        {
-            public object Key { get; set; }
-
-            public void Dispose()
-            {
-                RefCounted<SemaphoreSlim> item;
-                lock (SemaphoreSlims)
-                {
-                    item = SemaphoreSlims[Key];
-                    --item.RefCount;
-                    if (item.RefCount == 0)
-                        SemaphoreSlims.Remove(Key);
-                }
-                item.Value.Release();
-            }
-        }
-    }
-}