Adding more error logging for failed QUIC writes.

net/quic/quic_connection.cc

 // Copyright (c) 2012 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.
 
 #include "net/quic/quic_connection.h"
 
 #include <string.h>
 #include <sys/types.h>
 
 #include <algorithm>
@@ skipping 1525 matching lines @@
 
   stats_.bytes_sent += result.bytes_written;
   ++stats_.packets_sent;
   if (packet->transmission_type != NOT_RETRANSMISSION) {
     stats_.bytes_retransmitted += result.bytes_written;
     ++stats_.packets_retransmitted;
   }
 
   if (result.status == WRITE_STATUS_ERROR) {
     OnWriteError(result.error_code);
+    DLOG(ERROR) << ENDPOINT << "failed writing " << encrypted->length()
+                << "bytes "
+                << " from host " << self_address().ToStringWithoutPort()
+                << " to address " << peer_address().ToString();
     return false;
   }
 
   return true;
 }
 
 bool QuicConnection::ShouldDiscardPacket(const QueuedPacket& packet) {
   if (!connected_) {
     DVLOG(1) << ENDPOINT
              << "Not sending packet as connection is disconnected.";
@@ skipping 557 matching lines @@
   }
   for (const QuicFrame& frame : retransmittable_frames->frames()) {
     if (frame.type == CONNECTION_CLOSE_FRAME) {
       return true;
     }
   }
   return false;
 }
 
 }  // namespace net