The stream timingHash is read by getStreamStats() while it is read/write
for processRecords(), the latter is a more frequent operation so there's
no real benefit of using a read-write lock instead of simple mutex.
This singleton class will keep track of Ttag timing across all ports and GUIDs.
A bunch of FIXMEs/TODOs are pending for this class implementation; also this
class has not been hooked up to the rest of the code yet.
