fast path

Author: BrennanConroy

src/SignalR/server/Core/src/HubConnectionContext.cs

@@ -74,8 +74,12 @@ public HubConnectionContext(ConnectionContext connectionContext, HubConnectionCo
             _systemClock = contextOptions.SystemClock ?? new SystemClock();
             _lastSendTimeStamp = _systemClock.UtcNowTicks;
 
-            var maxInvokes = contextOptions.MaximumParallelInvocations;
-            ActiveInvocationLimit = new SemaphoreSlim(maxInvokes, maxInvokes);
+            // We'll be avoiding using the semaphore when the limit is set to 1, so no need to allocate it
+            var maxInvokeLimit = contextOptions.MaximumParallelInvocations;
+            if (maxInvokeLimit != 1)
+            {
+                ActiveInvocationLimit = new SemaphoreSlim(maxInvokeLimit, maxInvokeLimit);
+            }
         }
 
         internal StreamTracker StreamTracker

src/SignalR/server/Core/src/Internal/DefaultHubDispatcher.cs

@@ -259,7 +259,7 @@ private Task ProcessInvocation(HubConnectionContext connection,
             else
             {
                 bool isStreamCall = descriptor.StreamingParameters != null;
-                if (!isStreamCall && !isStreamResponse)
+                if (connection.ActiveInvocationLimit != null && !isStreamCall && !isStreamResponse)
                 {
                     return connection.ActiveInvocationLimit.RunAsync(state =>
                     {