QTime startTime = QTime::currentTime();
QThread::msleep(SLEEP_TIME_MILL);
QTime stopTime = QTime::currentTime();
int elapsed = startTime.msecsTo(stopTime);
qDebug()<<"QTime.currentTime ="<<elapsed<<"ms";
QTime startTime = QTime::currentTime();
QThread::msleep(SLEEP_TIME_MILL);
QTime stopTime = QTime::currentTime();
int elapsed = startTime.msecsTo(stopTime);
qDebug()<<"QTime.currentTime ="<<elapsed<<"ms";