code: protected function move(NodeConnectionInterface $connection, $slot)
      {
          $this->pool[(string) $connection] = $connection;
          $this->slots[(int) $slot] = $connection;
          $this->slotmap[(int) $slot] = $connection;
      }
docs: Permanently associates the connection instance to a new slot.
  The connection is added to the connections pool if not yet included.
  
  @param NodeConnectionInterface $connection Connection instance.
  @param int                     $slot       Target slot index.