(hopefully) fixes Shynixn/MCCoroutine#82

[Jupiops]

I was not sure if wakeUpBlockService.ensureWakeup() can safely be called if the plugin is not enabled, so I implemented it like this. If that's not how you expected it, please comment and I will change it.

Then I would implement it like:

wakeUpBlockService.ensureWakeup()
return plugin.isEnabled && plugin.server.isPrimaryThread