Update DoubleFetchHandler.cs

Author: Maddie Clayton

src/StackAdmin/Dns/Commands.Dns/Models/DoubleFetchHandler.cs

@@ -1,3 +1,17 @@
+ // ----------------------------------------------------------------------------------
+ //
+ // Copyright Microsoft Corporation
+ // Licensed under the Apache License, Version 2.0 (the "License");
+ // you may not use this file except in compliance with the License.
+ // You may obtain a copy of the License at
+ // http://www.apache.org/licenses/LICENSE-2.0
+ // Unless required by applicable law or agreed to in writing, software
+ // distributed under the License is distributed on an "AS IS" BASIS,
+ // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ // See the License for the specific language governing permissions and
+ // limitations under the License.
+ // ----------------------------------------------------------------------------------
+
 using System;
 using System.Net.Http;
 using System.Threading;