https://github.com/bitcoin/bitcoin/issues/12453
https://github.com/bitcoin/bitcoin/pull/12849 Adding logging for loop iteration level in p2p_sendheaders.py
https://github.com/bitcoin/bitcoin/pull/13192 [tests] Fixed intermittent failure in p2p_sendheaders.py.
https://github.com/bitcoin/bitcoin/pull/13350 [tests] Add logging to provide anchor points when debugging p2p_sendheaders
Also:
https://github.com/bitcoin/bitcoin/pull/13522 [tests] Fix p2p_sendheaders race