At present, the application of vlog in the code is quite confusing.
It is inherited from impala VLOG_XX format, and there is also VLOG(number) format.
VLOG(number) format does not have a unified specification, so this pr standardizes the use of VLOG
1. MonoTime/MonoDelta
MonoTime: The MonoTime represents a particular point in time, relative to some fixed but unspecified reference point.
MonoDelta: The MonoDelta class represents an elapsed duration of time, the delta between two MonoTime instances.
2. CountDownLatch
This is a C++ implementation of the Java CountDownLatch