Specifically proxied bodies would make use of an optimization in hyper
that resulted in the connection not knowing (but it did know! just
didn't tell itself...) that the body was finished, and so the connection
was closed. 0.12.7 includes the fix in hyper.
As part of this upgrade, the keep-alive tests have been adjusted to send
a small body, since the empty body was not triggering this case.
Sean McArthur
Oliver Gould