Took a look at the JSR223 wiki, unfortunately this is beyond my coding abilities. It still looks like all commands are sent through the OH2 Event Bus which would be the bottleneck.
Tested postCommand, it doesn’t work with LIFX. It seems like the OH devs are recommending Binding devs use one or the other.
I also tried connecting channels from multiple LIFX bulbs to a single Item, hoping to maybe get around the Event Bus single-threading, but no luck.