I think it depends on what the users are doing: If they use async code as just a more office synchronous/threaded code, with purely linear control flow, then n

I think it depends on what the users are doing: If they use async code as just a more office synchronous/threaded code, with purely linear control flow, then no knowledge of Pin is required. The users just sprinkle awaits and are good with it. If users also explore the areas of which are more unique to async code (e.g. real concurrency, select!, custom combinators, cancellation mechanisms, etc) than they will indeed run fairly early into Pin. I guess the majority of users who anticipated async/await fall into the first category. Most projects and requests around async code seem to be "just" webservers which handle some APIs. That will likely be the domain where one can live fairly well without Pin - at least if you do not implement the underlying webserver.