Merge pull request #1123 from svick/sockaddr-sequential

Specify sequential layout to avoid warning

src/Microsoft.AspNetCore.Server.Kestrel/Internal/Networking/SockAddr.cs

@@ -2,9 +2,11 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Net;
+using System.Runtime.InteropServices;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Internal.Networking
 {
+    [StructLayout(LayoutKind.Sequential)]
     public struct SockAddr
     {
         // this type represents native memory occupied by sockaddr struct