Returns the thread timestamp from the incoming event. Falls back to the message's own ts when thread_ts is absent (e.g. first message in a DM thread).
ts
thread_ts
The current turn context.
The thread timestamp, or undefined if not available.
undefined
Returns the thread timestamp from the incoming event. Falls back to the message's own
tswhenthread_tsis absent (e.g. first message in a DM thread).