PR12392 backport https://github.com/bitcoin/bitcoin/pull/12392/files
c4af738 Fix ignoring tx data requests when fPauseSend is set on a peer (Matt Corallo)
Pull request description:
This resolves a bug introduced in 66aa1d58a158991a8014a91335b5bc9c00062f56 where, if when responding to a series of transaction requests in a getdata we hit the send buffer limit and set fPauseSend, we will skip one transaction per call to ProcessGetData. Bug found by Cory Fields (@theuni). Probably worth slipping into 0.16 :/.
(cf D2606 - the corresponding diff of ours)