Motivation
It's totally acceptable for a HTTP server to respond before a request
upload has completed. If the response is an error, we should abort the
upload (and we do), but if the response is a 2xx we should probably just
finish the upload.
In this case it turns out we'll actually hit a crash when we attempt to
deliver an empty body message. his is no good!
Once that bug was fixed it revealed another: while we'd attempted to
account for this case, we hadn't tested it, and so it turns out that
shutdown would hang. As a result, I've also cleaned that up.
Modifications
- Tolerate empty circular buffers of bytes when streaming an upload.
- Notify the connection that the task is complete when we're done.
Result
Fewer crashes and hangs.