fixed TestKit build warnings (#7572)

Author: Aaronontheweb

src/core/Akka.Streams/ActorMaterializer.cs

@@ -258,13 +258,12 @@ private static ActorSystem ActorSystemOf(IActorRefFactory context)
     internal static class ActorMaterializerHelper
     {
         /// <summary>
-        /// TBD
+        /// Converts an <see cref="IMaterializer"/> to an <see cref="ActorMaterializer"/>.
         /// </summary>
-        /// <param name="materializer">TBD</param>
+        /// <param name="materializer">The original materializer.</param>
         /// <exception cref="ArgumentException">
         /// This exception is thrown when the specified <paramref name="materializer"/> is not of type <see cref="ActorMaterializer"/>.
         /// </exception>
-        /// <returns>TBD</returns>
         internal static ActorMaterializer Downcast(IMaterializer materializer)
         {
             //FIXME this method is going to cause trouble for other Materializer implementations

src/core/Akka.TestKit/CallingThreadDispatcher.cs

@@ -43,30 +43,19 @@ public override MessageDispatcher Dispatcher()
     public class CallingThreadDispatcher : MessageDispatcher
     {
         /// <summary>
-        /// TBD 
+        /// HOCON id of the CallingThreadDispatcher
         /// </summary>
-        public static string Id = "akka.test.calling-thread-dispatcher";
-
-        /// <summary>
-        /// TBD
-        /// </summary>
-        /// <param name="configurator">TBD</param>
+        public new static string Id = "akka.test.calling-thread-dispatcher";
+        
         public CallingThreadDispatcher(MessageDispatcherConfigurator configurator) : base(configurator)
         {
         }
-
-        /// <summary>
-        /// TBD
-        /// </summary>
-        /// <param name="run">TBD</param>
+        
         protected override void ExecuteTask(IRunnable run)
         {
             run.Run();
         }
-
-        /// <summary>
-        /// TBD
-        /// </summary>
+        
         protected override void Shutdown()
         {
             // do nothing