bind executor to subscribe/publish

I would like to ask, is there any way to make the subscribe callback run in the specified executor thread API.

In addition, is the listener object multi-threaded when listening to multiple subscribers? Is it possible to configure the number of threads?

Start by locating the subscribe and publish callback APIs and the listener implementation. Determine whether callbacks can use a specified executor, how listeners behave with multiple subscribers, and whether thread-count configuration is intended. Done means the requested threading behavior and configuration are clearly defined and supported, with corresponding tests or documentation.

Written by the indexing model from the issue text.