public function close() : Promised
    {
        return
            ($this->pool
                ? $this->pool->shutdown()
                : (
                    $this->session
                        ? $this->session->close()
                        : Promise::resolved()
                )
            )->sync($this->closed())
        ;
    }
public function close() : Promised
    {
        return
            ($this->pool
                ? $this->pool->shutdown()
                : (
                    $this->session
                        ? $this->session->close()
                        : Promise::resolved()
                )
            )->sync($this->closed())
        ;
    }
public function close ( ) : Promised { return ( $ this -> pool ? $ this -> pool -> shutdown ( ) : ( $ this -> session ? $ this -> session -> close ( ) : Promise :: resolved ( ) ) ) -> sync ( $ this -> closed ( ) ) ; }
close pool connections or session client
@return Promised
close pool connections or session client