Consider a Stopwatch API that accept a lambda and returns a Duration

[kluever]

E.g.,
Duration elapsed = Stopwatch.measure(() -> <code goes here>);

[kevinb9n]

Supporting void lambdas sound great.

[ogregoire]

This seems to be very limiting since the result of non-void lambdas can't be used.

Maybe a TimedResult<T> can be returned, so that both the duration and the actual result can be retrieved?

[netdpb]

Relevant to discussion in #3528.

[kluever]

@FuncGuy Thanks for getting this started.

Unfortunately there's a bit more work that needs to happen before we can start reviewing this PR. See the steps here, specifically:

Note: We know it's tempting to submit code before the feature is accepted, but this is not always a good use of your time. First, the community has to discuss whether the feature is a good fit for Guava, then the API gets hammered out, and then code happens. Sending in code won't help a feature request get accepted.

We have a fairly rigorous API review process that someone (most likely I) will have to follow before we touch any code. I'll try to prioritize that sometime in the next few weeks.

Thanks again!