UserInterfaceUpdate or CriticalSections in Web 1?

In this scenario. server threads looking at the file system are used to update a global variable that is accessed by Web pages, other threads, or objects. In this case, does UserInterfaceUpdate have the effect of pausing execution of the updating tread to allow the global variable to be written via the main (App) thread? Or is it better to use critical sections if potentially multiple threads could write to the same global variable? Or have I missed a step and if so what?

Xojo’s threading is cooperative. In most cases no CriticalSection is needed to update something.

So what do you do?

It’s for distributed logging involving processing out of order messages because of different latencies between nodes connected via different routes, some redundant with duplicates. So I need to avoid race conditions. A colleague used UserInterfaceUpdate in a simpler scenario. Xojo’s Spanish-Language Evangelist suggests it’s a “bridge” to the main thread. But what does this metaphor mean?