Added inline documentation to each helper function (addLocation, deleteLocation,
addEcLocation, deleteEcLocation) explaining the two-level locking strategy:
- RLock on vidMapLock prevents resetVidMap from swapping the pointer
- vidMap has internal locks that protect the actual map mutations
- This design provides optimal concurrency
The comments make it clear why RLock (not Lock) is correct and intentional,
preventing future confusion about the locking strategy.