code: public function removeById($connectionID)
      {
          if (isset($this->pool[$connectionID])) {
              $this->slotmap->reset();
              $this->slots = array_diff($this->slots, array($connectionID));
              unset($this->pool[$connectionID]);
  
              return true;
          }
  
          return false;
      }
docs: Removes a connection instance by using its identifier.
  
  @param string $connectionID Connection identifier.
  
  @return bool True if the connection was in the pool.