Run func should use context instead of stop channel #198
Description
It is preferable to use a context instead of a stop channel when controlling the lifetime of a function call (either long-lived goroutine or just RPC calls). Context makes it easier to propagate cancellation and still allow operations with short timeouts in a long-lived routine.
Additionally, our code will be easier to test if functions like Run() wait for their child goroutines to exit before returning themselves. This provides tests with a way to guarantee that all side-effects of a particular call have been executed.