(mongodb >=1.13.0)
MongoDB\Driver\ServerDescription::getLastUpdateTime — Returns the server's last update time in microseconds
Returns the server's last update time in microseconds.
注意: The returned value is a monotonic timestamp, which starts at an arbitrary point. As such, it is only suitable to compare with other return values from MongoDB\Driver\ServerDescription::getLastUpdateTime().
此函数没有参数。
Returns the server's last update time in microseconds.