Use clock package in _TimeIntervalStreamSink (and maybe others) #660
Description
In order to deterministically test async code, the fakeAsync package currently seems to be the way to go.
Unfortunately, it cannot modify the StopWatch from dart:core, and instead it is recommended to use the clock package which describes itself as
This package provides a Clock class which encapsulates the notion of the "current time" and provides easy access to points relative to the current time. Different Clocks can have a different notion of the current time, and the default top-level clock's notion can be swapped out to reliably test timing-dependent code.
Would it be possible to use this package in _TimeIntervalStreamSink and possibly other places, in order to allow deterministic testing using fakeAsync?
I'd be happy to contribute a corresponding PR!