code: def send_error(self, error):
          
  
          error_message = build_raw_error_message(error)
          write_future = self.writer.put(error_message)
          write_future.add_done_callback(
              lambda f: IOLoop.current().add_callback(
                  self.tchannel.event_emitter.fire(
                      EventType.after_send_error,
                      error,
                  )
              )
          )
          return write_future
docs: Convenience method for writing Error frames up the wire.
  
          :param error:
              TChannel Error. :py:class`tchannel.errors.TChannelError`.
          :returns:
              A future that resolves when the write finishes.