Profiler to record into. If null, the zone is ignored. This enables 'optional profiling', where instrumenting code (zones) is always present in the code but only activated when a Profiler exists.
Zone information string. Used to recognize zones when parsing and accumulating profile data. Can be the 'name' of the zone, possibly with some extra _info (e.g. "frame": entire frame or "batch 5": fifth draw batch). Must not be empty or longer than 255 characters and must not contain zero ('\0') characters.
Construct a zone to record with specified _profiler.
Emits the zone start event.