Icicle\Concurrent\Process\Process::getStdIn PHP Method

    public function getStdIn() : WritableStream
    {
        if (null === $this->stdin) {
            throw new StatusError('The process has not been started.');
        }
        return $this->stdin;
    }

    /**
     * {@inheritdoc}
     */
    public function start()
    {
        $this->process->start();

        $this->channel = new Channel($this->process->getStdOut(), $this->process->getStdIn());
    }