Improve core performance

**Feature request**
It would be great to have logging for handlers.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_logging` with default `false`.

Start by locating the handler execution path and the configuration parsing or defaults for the new enable_logging option. Confirm how handler events should be logged, keep logging disabled by default, and verify the behavior in a production-style run or the project's existing tests.

Written by the indexing model from the issue text.