code: def _on_send_complete(self, handle, error):
          
          assert handle is self._handle
          self._write_buffer_size -= 1
          assert self._write_buffer_size >= 0
          if self._error:
              self._log.debug('ignore sendto status {} after error', error)
          # See note in _on_write_complete() about UV_ECANCELED
          elif error and error != pyuv.errno.UV_ECANCELED:
              self._log.warning('pyuv error {} in sendto callback', error)
              self._protocol.error_received(TransportError.from_errno(error))
          self._maybe_resume_protocol()
          self._maybe_close()
docs: Callback used with handle.send().