src/Consumer.php
public function start(?callable $consumer = null): void
    {
        if ($this->process !== null) {
            $this->error('Consumer is already being executed');
            return;
        }

        $this->setupStopStrategy();

        $this->process = $this->createProcess($consumer);
        $this->process->start();

        Loop::run();
    }
public function start(?callable $consumer = null): void
    {
        if ($this->process !== null) {
            $this->error('Consumer is already being executed');
            return;
        }

        $this->setupStopStrategy();

        $this->process = $this->createProcess($consumer);
        $this->process->start();

        Loop::run();
    }
start consumer

@access public