Amp\Artax\HttpTunneler::enableWriteWatcher PHP Method

    private function enableWriteWatcher(HttpTunnelStruct $struct)
    {
        if ($struct->writeWatcher === null) {
            $struct->writeWatcher = \Amp\onWritable($struct->socket, function () use($struct) {
                $this->doWrite($struct);
            });
        }
    }