Atlas analysis monitor dynamic branch hooks

even if you did want to do the dup detection and raise an exception, this is another instance of O(1) vs O(N) data structures being used.  ( think of the case where you come back next week needing for some weird reason to add 1000 branch handlers.  now for each add you iterate over all previously added rather than use a hash index to decide if a value is present which makes construction of this object very slow and subsequently perf falls off )