constants.me was previously added in https://github.com/Incubaid/arakoon/pull/70/files#L1L36 , now it's made explicit in the Logger.debug_f_ "%s: previous_format_string" (which is the biggest part of this changeset).
I have however not changed the construction of any ELog effects, so these don't have 'me' in the string being built yet, as it was before. So I don't think constants.me is being logged twice.
(Most ELog statements btw are written with a (fun () -> Printf.sprintf ...) in them, this could be made nicer by introducing a specific macro for this, which I have not done in this change.)

Hmm, now that I think of it, I could've phrased this line as:
+    | ELog build          -> Logger.debug_f_ "%s: PURE: %s" constants.me (build ())
which would've been nicer but that probably doesn't matter too much :-)