With Infinispan 15 the threads for indexing are taken from the Infinispan blocking queue, the Hibernate Search pool is not instantiated anymore.

So the index writer cache property `thread pool size` is basically not used anyway by the system.

We could use the limited Blocking Executor feature of the BlockingManager to honor the property again. This would ensure that HS would not use too many threads from our blocking manager as the user can configure.