check user_handlers on timer stop

[ivan4th]

Looks good, but a couple of points:

• Perhaps this PR should include a revert of 40613cde233f68144f2ba182362e0faf84c6b2bf (otherwise there's a conflict)
• It would be easier to scan the logs for timer errors if the messages related to timer problems have a common prefix such as timer error:

[RoadRunnr]

Looks good, but a couple of points:

• Perhaps this PR should include a revert of 40613cd (otherwise there's a conflict)
• It would be easier to scan the logs for timer errors if the messages related to timer problems have a common prefix such as timer error:

both done

[ivan4th]

@RoadRunnr do we still need this PR after we merged #341?

[korroot]

Closing as all relevant changes are included in #341