Configurable shared executor service for com.rabbitmq.client.impl.ConsumerWorkService

[retriku]

We have found necessity to provide shared java.util.concurrent.ExecutorService to com.rabbitmq.client.impl.ConsumerWorkService. This is because default executor service uses twice the number of Runtime.getRuntime().availableProcessors(), which turns out to be too big for our needs, leading to wasted resources. Also current implementation restricts our ability to test latest thread pool by Cats Effect 3, which is used for both non-blocking and blocking operations (since 3.3.2). See https://discord.com/channels/632277896739946517/632278585700384799/943070620621619251, also in https://typelevel.org/cats-effect/docs/migration-guide#blocker.

I suggest following RabbitClient takes some ec: Option[F[ExecutionContext]] = None, which is then used like ec.getOrElse(Async[F].executionContext). What do you say @jbwheatley ?

[retriku]

Solved since version 5.0.0