Close connections immediately (when we know that we can do that)

[neongreen]

Fixes #490.

I'm going to test this in https://github.com/wireapp/wire-server so please don't merge that yet. @LeifW @naushadh @dsturnbull would you also like to take a look?

[neongreen]

So there's a choice of two commits now:

• one does sinkNull
• the other closes the connections without sinking anything

The latter is several times faster in my benchmarks (five times faster for SQS's deleteMessage with local fake SQS), but I'm not sure it's correct. On the other hand, I also don't see any reason why it wouldn't be correct, but it still seems suspicious.

[naushadh]

I too would prefer the faster way, correctness provided. Perhaps long term we really do need some actual testing against AWS (or a mock of it) (#477) and/or lift connection handling into the type system.

[neongreen]

This is in production in https://github.com/wireapp/wire-server now and things haven't broken yet, so I'm in favor of merging it. cc @MichaelXavier?

[dzhus]

Same here – seems ok to merge

[mheinzel]

I rebased this change, which we have been running in production in https://github.com/wireapp/wire-server for over a year at this point.

Some CI builds failed because of happy, one because of "No output has been received in the last 10m0s", but this seems to happen on master, too.

If there is any interest in merging this, that would be great. If not, we'll keep using our fork.
Let me know if there is anything I could do to help make this happen.

[brendanhay]

LGTM

[mheinzel]

Wow, thanks for the quick response!