code: public function open()
      {
          try
          {
              $additionalConnectionOptions = array();
              foreach (array('connection_timeout', 'read_write_timeout', 'keepalive', 'heartbeat') as $option) {
                  if (isset($this->$option)) {
                      $additionalConnectionOptions[$option] = $this->$option;
                  }
              }
              $this->AMQPConnection = new AMQPSSLConnection(
                  $this->host,
                  $this->port,
                  $this->username,
                  $this->password,
                  $this->vhost,
                  $this->ssl_context_options,
                  $additionalConnectionOptions
              );
              $this->channel = $this->AMQPConnection->channel();
              $this->channel->queue_declare($this->queue_name, false, false, false, false);
              $this->channel->exchange_declare($this->exchange, $this->exchange_type, false, true, false);
              $this->channel->queue_bind($this->queue_name, $this->exchange);
          }
          catch (Exception $e)
          {
              throw new Exception($e);
          }
      }
docs: Open a connection with the RabbitMQ Server
  
  @return void