public void setXON(boolean value) throws IOException {
            setConfigSingle(value ? SILABSER_SET_XON_REQUEST_CODE : SILABSER_SET_XOFF_REQUEST_CODE, 0);
        }
emulate external XON/OFF
@throws IOException
usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Cp21xxSerialDriver.java