Add support for configuring Pulsar client IO and listener threads

[vpavic]

This commit adds configuration properties that allow users to configure number of IO threads and listener threads used by the Pulsar client.

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From my experience with Pulsar, using these settings is often needed to achieve the optimal setup of the Pulsar client so ideally Spring Boot's auto-config would provide a way to do this using configuration properties.

/cc @onobc

[onobc]

From my experience with Pulsar, using these settings is often needed to achieve the optimal setup of the Pulsar client so ideally Spring Boot's auto-config would provide a way to do this using configuration properties.

Thanks for the contribution @vpavic . When we brought the auto-configuration into Spring Boot we greatly reduced the number of configuration properties we supported. We wanted the community to let us know which properties were important. Thank you for doing that here. Let's see what the Boot team thinks.

[philwebb]

It sounds like they'd be useful for a lot of apps so I'm in favor of adding them. I wonder if we should put them under a nested Threads class (similar to server.tomcat.thread.<name>)?

[onobc]

It sounds like they'd be useful for a lot of apps so I'm in favor of adding them. I wonder if we should put them under a nested Threads class (similar to server.tomcat.thread.<name>)?

I think grouping them under thread would be a good forward-thinking idea. The naming here is interesting....

• ioThreads -> thread.num-io or thread.io ?
• listenerThreads -> thread.num-listener or thread.listener ?

[philwebb]

I would suggest something similar to existing tomcat ones. threads.io and threads.listener would be my suggestion.

[vpavic]

I've updated the PR accordingly.

[philwebb]

Thanks @vpavic! Merged into main.