MBT plugin does not correctly report traces when running a build in parallel

[sameagen-MW]

This is due to how the plugin class is copied onto parpool workers, with some data not being successfully synchronized. I should have some time to fix this soon.

Essentially tasks which run on parallel workers do not create traces. Here's an example:

In serial:

In parallel:

[sameagen-MW]

Not planning on supporting this currently unless we hear a desire for it from users. If you are a user reading this and this functionality would be valuable to your workflow, please use this issue to communicate with us!