I've seen a few questions about having a `timeout(...

# coroutines

[baxter]

I've seen a few questions about having a timeout() operator for flow (similar to Rx), so I created a PR with this operator implemented. https://github.com/Kotlin/kotlinx.coroutines/pull/2597
This operator will only timeout if the upstream fails to emit after the set period of time, but ignores the time spent collecting.