Added closeSseStream method to StreamableHttpServerTransport for managing SSE stream lifecycle and updated API signature.

Author: devcrocod

kotlin-sdk-server/api/kotlin-sdk-server.api

@@ -160,8 +160,9 @@ public final class io/modelcontextprotocol/kotlin/sdk/server/StdioServerTranspor
 public final class io/modelcontextprotocol/kotlin/sdk/server/StreamableHttpServerTransport : io/modelcontextprotocol/kotlin/sdk/shared/AbstractTransport {
 	public static final field STANDALONE_SSE_STREAM_ID Ljava/lang/String;
 	public fun <init> ()V
-	public fun <init> (ZZLjava/util/List;Ljava/util/List;Lio/modelcontextprotocol/kotlin/sdk/server/EventStore;)V
-	public synthetic fun <init> (ZZLjava/util/List;Ljava/util/List;Lio/modelcontextprotocol/kotlin/sdk/server/EventStore;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (ZZLjava/util/List;Ljava/util/List;Lio/modelcontextprotocol/kotlin/sdk/server/EventStore;Ljava/lang/Long;)V
+	public synthetic fun <init> (ZZLjava/util/List;Ljava/util/List;Lio/modelcontextprotocol/kotlin/sdk/server/EventStore;Ljava/lang/Long;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun closeSseStream (Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	public fun close (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	public final fun getSessionId ()Ljava/lang/String;
 	public final fun handleDeleteRequest (Lio/ktor/server/application/ApplicationCall;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
@@ -195,4 +196,3 @@ public final class io/modelcontextprotocol/kotlin/sdk/server/WebSocketMcpServerT
 	public fun <init> (Lio/ktor/server/websocket/WebSocketServerSession;)V
 	public synthetic fun getSession ()Lio/ktor/websocket/WebSocketSession;
 }
-

kotlin-sdk-server/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/server/StreamableHttpServerTransport.kt

@@ -239,6 +239,24 @@ public class StreamableHttpServerTransport(
         }
     }
 
+    /**
+     * Closes the SSE stream associated with the given [requestId], prompting the client to reconnect.
+     * Useful for implementing polling behavior for long-running operations.
+     */
+    public suspend fun closeSseStream(requestId: RequestId) {
+        if (enableJsonResponse) return
+        val streamId = requestToStreamMapping[requestId] ?: return
+        val sessionContext = streamsMapping[streamId] ?: return
+
+        try {
+            sessionContext.session?.close()
+        } catch (e: Exception) {
+            _onError(e)
+        } finally {
+            streamsMapping.remove(streamId)
+        }
+    }
+
     override suspend fun close() {
         streamMutex.withLock {
             streamsMapping.values.forEach {