Add mock writem in AsyncUDPSocket

Summary: Add writem method to MockAsyncUDPSocket.

Reviewed By: yfeldblum

Differential Revision: D33696768

fbshipit-source-id: eb99650f3dcde4eacbf83be3dd8ef9d2c03c6200

folly/io/async/test/MockAsyncUDPSocket.h

@@ -33,6 +33,11 @@ struct MockAsyncUDPSocket : public AsyncUDPSocket {
   MOCK_METHOD2(setFD, void(NetworkSocket, AsyncUDPSocket::FDOwnership));
   MOCK_METHOD2(
       write, ssize_t(const SocketAddress&, const std::unique_ptr<IOBuf>&));
+  MOCK_METHOD3(
+      writem,
+      int(Range<SocketAddress const*>,
+          const std::unique_ptr<folly::IOBuf>*,
+          size_t));
   MOCK_METHOD3(
       writeGSO,
       ssize_t(