Fix/issues with running commandprocessor samples

samples/CommandProcessor/HelloWorldAsync/GreetingCommandRequestHandlerAsync.cs

@@ -36,7 +36,7 @@ internal class GreetingCommandRequestHandlerAsync : RequestHandlerAsync<Greeting
         [RequestLoggingAsync(step: 1, timing: HandlerTiming.Before)]
         public override async Task<GreetingCommand> HandleAsync(GreetingCommand command, CancellationToken cancellationToken = default)
         {
-            Console.WriteLine("Hello {0}}", command.Name);
+            Console.WriteLine("Hello {0}", command.Name);
 
             return await base.HandleAsync(command, cancellationToken).ConfigureAwait(ContinueOnCapturedContext);
         }

samples/CommandProcessor/HelloWorldInternalBus/GreetingCommandHandler.cs

@@ -1,4 +1,4 @@
-#region Licence
+#region Licence
 /* The MIT License (MIT)
 Copyright © 2015 Ian Cooper <ian_hammond_cooper@yahoo.co.uk>
 
@@ -29,13 +29,13 @@ THE SOFTWARE. */
 
 namespace HelloWorld
 {
-    internal class GreetingCommandHandler : RequestHandler<GreetingCommand>
+    internal class GreetingCommandHandler : RequestHandlerAsync<GreetingCommand>
     {
-        [RequestLogging(step: 1, timing: HandlerTiming.Before)]
-        public override GreetingCommand Handle(GreetingCommand command)
+        [RequestLoggingAsync(step: 1, timing: HandlerTiming.Before)]
+        public override async Task<GreetingCommand> HandleAsync(GreetingCommand command, CancellationToken cancellationToken)
         {
             Console.WriteLine("Hello {0}", command.Name);
-            return base.Handle(command);
+            return await base.HandleAsync(command, cancellationToken);
         }
     }
 }

src/Paramore.Brighter/RequestHandlerAsync.cs

@@ -83,6 +83,9 @@ public abstract class RequestHandlerAsync<TRequest> : IHandleRequestsAsync<TRequ
         /// <param name="successor">The successor.</param>
         public void SetSuccessor(IHandleRequestsAsync<TRequest> successor)
         {
+            if (this == successor)
+                return;
+
             _successor = successor;
         }