public function cancel($consumer_tag = '') {

        if($consumer_tag === '')
            $consumer_tag = $this->consumer_tag;

        try {
            $this->channel->_getChannel()->basic_cancel($consumer_tag);
        } catch (AMQPRuntimeException $e) {
            throw new AMQPConnectionException($e->getMessage(), $e->getCode(), $e->getPrevious());
        } catch (Exception $e) {
            return false;
        }

        return true;
    }