PHPDaemon\Network\IOStream::setWatermark PHP Method

    public function setWatermark($low = null, $high = null)
    {
        if ($low !== null) {
            $this->lowMark = $low;
        }
        if ($high !== null) {
            $this->highMark = $high;
        }
        if ($this->highMark > 0) {
            $this->highMark = max($this->lowMark, $this->highMark);
        }
        $this->bev->setWatermark(\Event::READ, $this->lowMark, $this->highMark);
    }