[TACHYON-220] WIP Comments describing issues and possible solutions 

Some initial comments to help improve the performance of master info. From what I gather there is locking on stack local objects that are never really put back into the map. I would appreciate suggestions before implementing it, hence the WIP tag.
Until the concurrency controls are pushed into the collection, you would still need this. Would have to look closer to see if anything depends on this in the call site