[h0l0gr4ph1c]

By opt in I mean I can opt in to using an executor if I want async. If I don't code still works and is might not be as performant.

Couldn't you have made another hard constraint to make async code work as normal if the programmer wanted?

[steveklabnik]

An executor is required, in name or in spirit. Every async system has software that does this. Most language runtimes that do simply give you no choice in the matter.

[h0l0gr4ph1c]

Rust is a language that does things different to other languages because it is a better way. I challenge you to do the same with Async. There is a different better way.