Comment by ChrisMarshallNY

I do a lot of it, but never on the low-end.

99% of mine, is responding to closures for network events and device responses.

When you do that, synchronizing is one way to deal with things (wait for the other thing to finish), or completion testing (is the thing ready for the next step?). Basically, they are the same thing.

You are also not always guaranteed a standard context, but modern languages make it easy to hook to one. In the "old days," we used to use RefCons (Reference Context hooks).