ofSerial writeByte issue

i'm not too sure is this a bug or what,i'm testing a really simple app which send command to trigger the arduino delay module

something like this:

serial.enumerateDevices();
vector deviceList = serial.getDeviceList();
int baud = 9600;
serial.setup("COM3", baud); // windows example

if (key == OF_KEY_F3)
{

		serial.writeByte('1');
		ofSleepMillis(100);



}

if i'm keep sending to the arduino,after the 5-6 times, the ofSerial somtimes reports couldn't write to the port,got
no response at all. or it just not trigger immediately have to wait like 5-8s to get responsed.

but same code in processing,seems working really fine,each time when i pressed the command key the arduino will be trigger immediately.

under the windows 10, OF version github 090 ,does anyone got same issue?
cheers