It would be nice to have an API which basically takes an array of Threads (or thread IDs), and which, if set, only records the thread local events for threads that are in that set. All other (thread local) events will simply be discarded.

The way this would be used, would be to start a recording, potentially with thresholds set very low. Next this laser pointer would shine a light on the next thread doing 'interesting work'. This interesting work could for example be defined by a thread starting to work on something related to an OpenTracing span that is being tracked.

This is an optimisation for being able to routinely do full tracing of executions of interest, whilst keeping full system overhead down.