Global variables sharing with mutex

So it sounds like there are no other options for using global variables in multi-user mode. Would it be possible at least to create a memory sharing feature between callbacks (feature request)? More specifically, memory sharing between callbacks that isn’t integral to the interface at all. Perhaps this would go well with the multiple outputs in callback that I have seen suggested as well?

Still good to know that everything will still work in single user mode, thanks for confirming!