Resolves an infinite loop when receiving data

[ketzusaka]

Per the system recv API if the other side of the connection returns 0 bytes the peer has performed an orderly shutdown. Because of this, if Hummingbird's receive returns an empty array, that indicates the connection is closed properly. This updates Vapor code to respect that condition and not continue to loop if the peer is closed.

This issue is causing servers to run at full load. Special thanks to linode for alerting me haha.

[tanner0101]

Can you test this against the following command wrk -d10 -c128 -t4 http://localhost:8000/plaintext --header="Connection: keep-alive" and let me know if you get any errors from Vapor.

[ketzusaka]

I do get some errors from that, but ab works fine. I'm not sure why there are extra empty lines getting sent in, but I'm investigating some directly with Hummingbird to see how the socket infrastructure works with wrk