This is the portion that I was seeking his feedback on. Rust originally was designed to work with OS native threads. Later Nginx like software emulated threads were proven far more efficient and fast. Here a single thread jumps from connection to connection, instead of waiting for the other side to respond. In C you can do it but you need the ability for a function to resume from the mid of its body where it left off. That asks for "co-routines" which even though possible makes the code complex.
Rust solution is async/await. But now they have two solutions, the more integrated multi threads and then this newly introduced single threaded async/await. It's better to get feedback from people that have worked on it and their good or bad experience.