How to enable log file auto flushing?

I've been struggling with the REST API and I was wondering if there was some way to configure auto flushing of the Redmine log file? The only way I've figured out how to force a flush of the log is to shutdown Redmine.

I see the additional_environment.rb file and I suspect there is something I can do in here, but I haven't been able to figure it out yet.

Thanks,
Cory