Add request and response for async search status

Author: stevejgordon

src/Nest/XPack/AsyncSearch/Status/AsyncSearchStatusRequest.cs

@@ -0,0 +1,20 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+namespace Nest
+{
+	[MapsApi("async_search.status.json")]
+	[ReadAs(typeof(AsyncSearchStatusRequest))]
+	public partial interface IAsyncSearchStatusRequest { }
+
+	/// <inheritdoc cref="IAsyncSearchStatusRequest"/>
+	public partial class AsyncSearchStatusRequest
+	{
+	}
+
+	/// <inheritdoc cref="IAsyncSearchStatusRequest"/>
+	public partial class AsyncSearchStatusDescriptor
+	{
+	}
+}

src/Nest/XPack/AsyncSearch/Status/AsyncSearchStatusResponse.cs

@@ -0,0 +1,17 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+using System.Runtime.Serialization;
+
+namespace Nest
+{
+	public class AsyncSearchStatusResponse : AsyncSearchResponseBase
+	{
+		[DataMember(Name = "_shards")]
+		public ShardStatistics Shards { get; internal set; }
+
+		[DataMember(Name = "completion_status")]
+		public int? CompletionStatus { get; internal set; }
+	}
+}