Signed-off-by: Callum Brown <callum@calcuode.com> This is part of my GSoC project implementing [MSC3231](https://github.com/matrix-org/matrix-doc/pull/3231).
This doc is short but a useful guide to what the request log lines mean. Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Co-authored-by: Erik Johnston <erik@matrix.org> Co-authored-by: Daniele Sluijters <daenney@users.noreply.github.com>