Sending status change notifications from server (#186)

* Sending status change notifications from server

src/Microsoft.SqlTools.ServiceLayer/LanguageServices/Contracts/StatusChangedNotification.cs

@@ -0,0 +1,35 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using Microsoft.SqlTools.ServiceLayer.Hosting.Protocol.Contracts;
+
+namespace Microsoft.SqlTools.ServiceLayer.LanguageServices.Contracts
+{
+    /// <summary>
+    /// Parameters sent back with an status change event
+    /// </summary>
+    public class StatusChangeParams
+    {
+        /// <summary>
+        /// URI identifying the text document
+        /// </summary>
+        public string OwnerUri { get; set; }
+
+        /// <summary>
+        /// The new status for the document
+        /// </summary>
+        public string Status { get; set; }
+    }
+
+    /// <summary>
+    /// Event sent for language service status change notification
+    /// </summary>
+    public class StatusChangedNotification
+    {
+        public static readonly
+           EventType<StatusChangeParams> Type =
+           EventType<StatusChangeParams>.Create("textDocument/statusChanged");
+    }
+}