[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.
"change inode as much as you like but the value of "somekey" in the map is not overwritten until you do a hashmap.put("somekey",inode)"

Since your last comment makes this statement a bit more clear. You are stating that changing the variable to point to a new object has no effect on the map; this is a very true statement. My comment was that if you mutate anything in the object that is at the current variable, then those mutations must be protected against.