Word of warning: using item lock instead of attribute lock _may_ serialize serving up items even from a hosted repository, as Nexus does _write_ to attributes things like last requested etc even for RO requests (ie. HTTP GET). How locks are "upgraded" (from shared to exclusive) means that when attribute is updated would result in upgraded lock, held until the very end of request. See NEXUS-4628

This could be a non-issue (I'd imagine it could affect a "swarm" building same thing, requesting same things like a CI), but still, I'd like to see some proof this does not affect (very badly) Nexus perf.