code: def write(self, chunk: bytes) -> "Future[None]":
          
          future = None
          if self.stream.closed():
              future = self._write_future = Future()
              self._write_future.set_exception(iostream.StreamClosedError())
              self._write_future.exception()
          else:
              future = self._write_future = Future()
              self._pending_write = self.stream.write(self._format_chunk(chunk))
              future_add_done_callback(self._pending_write, self._on_write_complete)
          return future
docs: Implements `.HTTPConnection.write`.
  
          For backwards compatibility it is allowed but deprecated to
          skip `write_headers` and instead call `write()` with a
          pre-encoded header block.