From #137, just in case to not forget about it.
Like tmc::fork_clang(), but without forking. Like tmc::spawn(), but with HALO. Like co_await co_await tmc::fork_clang(), but perhaps a bit more optimized and/or with a bit cleaner/shorter calling convention?
Usecase: quickly run a named function / member function on a different executor and/or with a different priority level, but without the allocation overhead.
Can be achieved by using the utility awaitables for changing the executor/priority inside the function itself, but when it's desired to set them from the caller instead (leaving the caller with the original executor/priority).