Fix MAGN-2317

@lukechurch

This submission takes use of the following commit:
https://github.com/DynamoDS/Dynamo/commit/a567190311f09f4a8c7acab087d27a94783471d6

The submission make some changes to the original code to fix several errors because some code has changed ever since.

This submission fixes magn-2317.
If we only temporarily uses the event-handler, we need to remove it to reduce memory footprint after it is used.
But the controller is long-lived, so is the reactor. We do not necessarily need to remove it.