Mojo UDP API implementation.

mojo/services/public/interfaces/network/udp_socket.mojom

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import "mojo/services/public/interfaces/network/net_address.mojom"
 import "mojo/services/public/interfaces/network/network_error.mojom"
 
 module mojo {
 
 // UDPSocket and UDPSocketClient represent a UDP socket and its client. The
@@ skipping 45 matching lines @@
   //   ...
   //   service->ReceiveMorePackets(3);
   //   // The client expects 4 more calls to OnReceived().
   ReceiveMorePackets(uint32 number);
 
   // Sends data to the specified destination. The socket must be bound.
   // The method doesn't report the result of the operation.
   SendToAndForget(NetAddress addr, uint8[] data);
 
   // Sends data to the specified destination. The socket must be bound.
+  // On success, |result.code| is a non-negative number indicating how many
+  // bytes have been written. Otherwise, it is a network error code, including
+  // (but not limited to):
+  // - ERR_INSUFFICIENT_RESOURCES (-12): The service doesn't have sufficient
+  //   resource to complete the operation. One possible cause is that the client
+  //   tries to send too many packets in a short period of time.
   SendTo(NetAddress addr, uint8[] data) => (NetworkError result);
 };
 
 interface UDPSocketClient {
-  // |addr| and |data| are non-NULL on success.
+  // On success, |addr| and |data| are non-NULL, |result.code| is a non-negative
+  // number indicating how many bytes have been received.
   OnReceived(NetworkError result, NetAddress? addr, uint8[]? data);
 };
 
 }