Icicle\Concurrent\Forking\Fork::kill PHP Method

    public function kill()
    {
        if ($this->isRunning()) {
            // Forcefully kill the process using SIGKILL.
            posix_kill($this->pid, SIGKILL);
        }
        if (null !== $this->pipe && $this->pipe->isOpen()) {
            $this->pipe->close();
        }
        // "Detach" from the process and let it die asynchronously.
        $this->pid = 0;
        $this->channel = null;
    }