Add RequestType0 type and update related code

Author: Kapil Borle

src/PowerShellEditorServices.Protocol/LanguageServer/Shutdown.cs

@@ -14,8 +14,8 @@ namespace Microsoft.PowerShell.EditorServices.Protocol.LanguageServer
     public class ShutdownRequest
     {
         public static readonly
-            RequestType<object, object> Type =
-            RequestType<object, object>.Create("shutdown");
+            RequestType0<object, object, object> Type =
+            RequestType0<object, object, object>.Create("shutdown");
     }
 
     /// <summary>

src/PowerShellEditorServices.Protocol/MessageProtocol/ProtocolEndpoint.cs

@@ -132,6 +132,15 @@ public async Task Stop()
 
         #region Message Sending
 
+        public Task<TResult> SendRequest<TResult, TError, TRegistrationOption>(
+            RequestType0<TResult, TError, TRegistrationOption> requestType0)
+        {
+            return this.SendRequest<Object, TResult>(
+                RequestType<Object, TResult>.ConvertToReqestType(requestType0),
+                 null);
+        }
+
+
         /// <summary>
         /// Sends a request to the server
         /// </summary>
@@ -254,6 +263,18 @@ await this.protocolChannel.MessageWriter.WriteEvent(
 
         #region Message Handling
 
+        public void SetRequestHandler<TResult, TError, TRegistrationOption>(
+            RequestType0<TResult, TError, TRegistrationOption> requestType0,
+            Func<RequestContext<TResult>, Task> requestHandler)
+        {
+            SetRequestHandler(
+                RequestType<Object, TResult>.ConvertToReqestType(requestType0),
+                (param1, requestContext) =>
+                {
+                    return requestHandler(requestContext);
+                });
+        }
+
         public void SetRequestHandler<TParams, TResult>(
             RequestType<TParams, TResult> requestType,
             Func<TParams, RequestContext<TResult>, Task> requestHandler)

src/PowerShellEditorServices.Protocol/MessageProtocol/RequestType.cs

@@ -12,8 +12,18 @@ public class RequestType<TParams, TResult>
     {
         public string MethodName { get; private set; }
 
+        public static RequestType<TParams, TResult> ConvertToReqestType<TError, TRegistrationOption>(
+            RequestType0<TResult, TError, TRegistrationOption> requestType0)
+        {
+            return RequestType<TParams, TResult>.Create(requestType0.Method);
+        }
         public static RequestType<TParams, TResult> Create(string typeName)
         {
+            if (typeName == null)
+            {
+                throw new System.ArgumentNullException(nameof(typeName));
+            }
+
             return new RequestType<TParams, TResult>()
             {
                 MethodName = typeName

src/PowerShellEditorServices.Protocol/Server/LanguageServerBase.cs

@@ -55,7 +55,6 @@ protected virtual Task Shutdown()
         }
 
         private async Task HandleShutdownRequest(
-            object shutdownParams,
             RequestContext<object> requestContext)
         {
             // Allow the implementor to shut down gracefully