Move unused forked code to external directory (#1192)

* Move unused forked code to external directory

* Fix SLN build errors

* Add back resource provider core since it's referenced by main resource provider project

* Update PackageProjects step of pipeline

external/Microsoft.SqlTools.Hosting.v2/Protocol/RequestContext.cs

@@ -0,0 +1,57 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Collections.Concurrent;
+using Microsoft.SqlTools.Hosting.Contracts;
+using Microsoft.SqlTools.Hosting.Contracts.Internal;
+
+namespace Microsoft.SqlTools.Hosting.Protocol
+{
+    public class RequestContext<TResult> : IEventSender
+    {
+        internal readonly BlockingCollection<Message> messageQueue;
+        internal readonly Message requestMessage;
+        
+        public RequestContext(Message message, BlockingCollection<Message> outgoingMessageQueue)
+        {
+            // TODO: Either 1) make this constructor internal and provide a tes framework for validating
+            //       or 2) extract an interface for requestcontext to allow users to mock
+            requestMessage = message;
+            messageQueue = outgoingMessageQueue;
+        }
+        
+        public virtual void SendResult(TResult resultDetails)
+        {
+            Message message = Message.CreateResponse(requestMessage.Id, resultDetails);
+            messageQueue.Add(message);
+        }
+
+        public virtual void SendEvent<TParams>(EventType<TParams> eventType, TParams eventParams)
+        {
+            Message message = Message.CreateEvent(eventType, eventParams);
+            messageQueue.Add(message);
+        }
+
+        public virtual void SendError(string errorMessage, int errorCode = 0)
+        {
+            // Build the error message
+            Error error = new Error
+            {
+                Message = errorMessage,
+                Code = errorCode
+            };
+            Message message = Message.CreateResponseError(requestMessage.Id, error);
+            messageQueue.Add(message);
+        }
+
+        public virtual void SendError(Exception e)
+        {
+            // Overload to use the parameterized error handler
+            SendError(e.Message, e.HResult);
+        }
+    }
+}
+