Add IntelliSense binding queue (#73)

* Initial code for binding queue

* Fix-up some of the timeout wait code

* Add some initial test code

* Add missing test file

* Update the binding queue tests

* Add more test coverage and refactor a bit.  Disable reliabile connection until we can fix it..it's holding an open data reader connection.

* A few more test updates

* Initial integrate queue with language service.

* Hook up the connected binding queue into al binding calls.

* Cleanup comments and remove dead code

* More missing comments

* Fix build break.  Reenable ReliabileConnection.

* Revert all changes to SqlConnectionFactory

* Resolve merge conflicts

* Cleanup some more of the timeouts and sync code

* Address code review feedback

* Address more code review feedback

src/Microsoft.SqlTools.ServiceLayer/LanguageServices/QueueItem.cs

@@ -0,0 +1,67 @@
+//
+// 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.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
+{
+    /// <summary>
+    /// Class that stores the state of a binding queue request item
+    /// </summary>    
+    public class QueueItem
+    {
+        /// <summary>
+        /// QueueItem constructor
+        /// </summary>
+        public QueueItem()
+        {
+            this.ItemProcessed = new ManualResetEvent(initialState: false);
+        }
+
+        /// <summary>
+        /// Gets or sets the queue item key
+        /// </summary>
+        public string Key { get; set; }
+
+        /// <summary>
+        /// Gets or sets the bind operation callback method
+        /// </summary>
+        public Func<IBindingContext, CancellationToken, Task<object>> BindOperation { get; set; }
+
+        /// <summary>
+        /// Gets or sets the timeout operation to call if the bind operation doesn't finish within timeout period
+        /// </summary>
+        public Func<IBindingContext, Task<object>> TimeoutOperation { get; set; }
+
+        /// <summary>
+        /// Gets or sets an event to signal when this queue item has been processed
+        /// </summary>
+        public ManualResetEvent ItemProcessed { get; set; } 
+
+        /// <summary>
+        /// Gets or sets the task that was used to execute this queue item.
+        /// This allows the queuer to retrieve the execution result.
+        /// </summary>
+        public Task<object> ResultsTask { get; set; }
+
+        /// <summary>
+        /// Gets or sets the binding operation timeout in milliseconds
+        /// </summary>
+        public int? BindingTimeout { get; set; }
+
+        /// <summary>
+        /// Converts the result of the execution task to type T
+        /// </summary>
+        public T GetResultAsT<T>() where T : class
+        {
+            var task = this.ResultsTask;
+            return (task != null && task.IsCompleted && task.Result != null)
+                ? task.Result as T
+                : null;
+        }
+    }
+}