Motivation:
It's possible for channels to be closed without an error; and the
`RequestResponseHandler` should tolerate that by failing any promises
for which it does not have a response for.
Modifications:
- Add `ClosedBeforeReceivingResponseError`
- Fail outstanding promises with `ClosedBeforeReceivingResponseError` in
`RequestResponseHandler.channelInactive`
- Add a test.
Result:
Outstanding request promises are failed when the channel becomes inactive.
Motivation:
Frequently, people want to terminate their pipeline with a handler that
takes in requests & a promise and on receipt of the response just
fulfill that promise.
Modifications:
- add `RequestResponseHandler`
- remove outdated of contents from README.md
Result:
more useful handlers
