Thank you. The @lock macro helps solve a very specific problem, and I was not at all aware of it.
As I dug into the this issue, I discovered I did not really understand how the $ interpolation for Threads.@spawn works for structures (more discussion here). At any rate, now I’m trying to find a way to measure the impact of using lots of copy operations when all I want to do is read state for a very brief amount of time (but ensure that, for a few milliseconds, I see the full state exactly as it was when my calculation started, no updates). But during this, I may be spawning another process that does need the most up-to-date state…so I cannot lock updates to state during my calculation…
Looks like I need each spawned process to have it’s own copy. But given that only a few changes will happen during the spawned process, still seems like a waste to copy everything.