docs: def join(self, timeout: float = None) -> bool:
          """
          Joins on the thread associated with the response if it exists, or
          just returns after a no-op if no thread exists to join.
  
          :param timeout:
              Maximum number of seconds to block on the join before given up
              and continuing operation. The default `None` value will wait
              forever.
          :return:
              A boolean indicating whether or not a thread existed to join
              upon.
          """
          try:
              self.thread.join(timeout)
              return True
          except AttributeError:
              return False