docs: def clone(self):
          """
          Clone the box.
  
          :returns: A new box with the same item queue.
  
          The cloned box is not closed, no matter the initial state of the
          original instance.
          """
          result = AsyncBox(maxsize=self._maxsize, loop=self.loop)
          result._queue = self._queue
          result._can_read = self._can_read
          result._can_write = self._can_write
  
          return result