Add a NetworkSocket overload for AsyncUDPServerSocket->getFD

Summary: I missed one of the functions that needs a NetworkSocket overload in past iterations.

Reviewed By: yfeldblum

Differential Revision: D14237211

fbshipit-source-id: 6d0bd151ff636206a44940c88a2d48c339aa67de

folly/io/async/AsyncUDPServerSocket.h

@@ -148,6 +148,11 @@ class AsyncUDPServerSocket : private AsyncUDPSocket::ReadCallback,
     return socket_->getFD();
   }
 
+  NetworkSocket getNetworkSocket() const {
+    CHECK(socket_) << "Need to bind before getting Network Socket";
+    return socket_->getNetworkSocket();
+  }
+
   void close() {
     CHECK(socket_) << "Need to bind before closing";
     socket_->close();