feverzsj

I think the main issue is no compilers is mature enough for coroutines and other c++20 features. You can easily run into lots of weird compiler bugs using them.

c++20 coroutine implementations are still far from stable. Lots of weird bugs, ICEs. And cppcoro is simply unusable with msvc now. So I won't consider using them right now.

There's simply no any synchronization in asio's cancellation mechanism, so if your async ops were running on multithread executors, you have to make sure each op you pass to parallel_group...

The only missing find method is to find until end, and if not found, keeps previous position. It would be faster than find_field_unordered for ordered optional field.

> One good method that would solve that specific problem would be something like find_one_of("optional1", "optional2", "next_required_field") and have it return not only the value but tell you which one...

> I believe save/restore cxa global states is managed as part of the C++ runtime support for exception handling. In the case of TBB, exception handling is facilitated through functions...