Hires timers for tokio.
This is a drop-in replacement of tokio::time.
The API is a 1:1 replication. Please refer to the doc there.
Timers with the highest possible resolution from the operating system
are used. The feature time of tokio is not used and is not required.
Sub-millisecond granularity is achieved with:
timerfdin Linux (and Android).kqueuewithEVFILT_TIMERin *BSD and Apple's Darwin; specifically,NOTE_MACHTIMEis used in Darwin to obtain the similar resolution to GCD.CreateWaitableTimerExwithCREATE_WAITABLE_TIMER_HIGH_RESOLUTIONin Windows.