private void begin () {
	long t__send, dt;
	double rate;
	_t_send = System.currentTimeMillis();
	while (++times <= Utils.MAX) {
	    broadcast("TEST", String.format("%d", System.currentTimeMillis()));
	    if (times % Utils.STEP == 0) {
		t__send = System.currentTimeMillis();
		dt = t__send - _t_send;
		if (dt > 0)
		    rate = (double) (Utils.STEP * 1000) / (double) dt;
		else
		    rate = 0.0;
		Utils.out(pid, String.format("[SEND] %06d\trate %10.1f m/s", times, rate));
		_t_send = t__send;
	    }
	}
    }