fix: Added support for byte on NetworkVariable through codegen (#2953)

* fix: Added support for byte on NetworkVariable through codegen

the codegen wasn't picking byte  - it's because a variable of a type other than NetworkVariable<byte> (such as NetworkVariable<FixedString32Bytes>) is serializing a byte value as part of its delta serialization. Delta serialization was added in NGO 1.9, which is why it doesn't happen in previous versions. This code assumes the existence of a byte serializer, but if the user doesn't have a NetworkVariable<byte> in their code, the byte serializer won't be initialized by the codegen pass.
credits: Kitty Drapper

* fix: Converted serialization operation to their appropriate Safe counterparts

Fixed safety issue that would trigger exception on runtime

* fix

Using WriteByteSafe as opposed to WriteValueSafe.

* update

adding changelog entry

---------

Co-authored-by: NoelStephensUnity <noel.stephens@unity3d.com>

Author: Ufabsther

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -15,6 +15,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ### Fixed
 
+- Fixed issue where internal delta serialization could not have a byte serializer defined when serializing deltas for other types. Added `[GenerateSerializationForType(typeof(byte))]` to both the `NetworkVariable` and `AnticipatedNetworkVariable` classes to assure a byte serializer is defined. (#2953)
 - Fixed issue with the client count not being correct on the host or server side when a client disconnects itself from a session. (#2941)
 - Fixed issue with the host trying to send itself a message that it has connected when first starting up. (#2941)
 - Fixed issue where in-scene placed NetworkObjects could be destroyed if a client disconnects early and/or before approval. (#2923)

com.unity.netcode.gameobjects/Runtime/NetworkVariable/AnticipatedNetworkVariable.cs

@@ -51,6 +51,7 @@ public enum StaleDataHandling
 #pragma warning restore IDE0001
     [Serializable]
     [GenerateSerializationForGenericParameter(0)]
+    [GenerateSerializationForType(typeof(byte))]
     public class AnticipatedNetworkVariable<T> : NetworkVariableBase
     {
         [SerializeField]

com.unity.netcode.gameobjects/Runtime/NetworkVariable/NetworkVariable.cs

@@ -9,6 +9,7 @@ namespace Unity.Netcode
     /// <typeparam name="T">the unmanaged type for <see cref="NetworkVariable{T}"/> </typeparam>
     [Serializable]
     [GenerateSerializationForGenericParameter(0)]
+    [GenerateSerializationForType(typeof(byte))]
     public class NetworkVariable<T> : NetworkVariableBase
     {
         /// <summary>

com.unity.netcode.gameobjects/Runtime/NetworkVariable/NetworkVariableSerialization.cs

@@ -717,7 +717,7 @@ public unsafe void WriteDelta(FastBufferWriter writer, ref T value, ref T previo
                 writer.WriteValueSafe(value);
                 return;
             }
-            writer.WriteByte(0);
+            writer.WriteByteSafe(0);
             BytePacker.WriteValuePacked(writer, value.Length);
             writer.WriteValueSafe(changes);
             unsafe
@@ -766,7 +766,7 @@ public unsafe void ReadDelta(FastBufferReader reader, ref T value)
                 {
                     if (changes.IsSet(i))
                     {
-                        reader.ReadByte(out ptr[i]);
+                        reader.ReadByteSafe(out ptr[i]);
                     }
                 }
             }