For years one of my primary tasks as a Mojolicious Core Team member has been to teach Mojolicious users the ins and outs of asynchronous programming. We have championed several patterns to tame the beast and clean up async code, including continuation passing, promises and now async/await. But while promises were a noted improvement over continuation passing, it is becoming more and more clear that the async/await pattern is a paradigm shift in asynchronous programming semantics.
I personally believe that it is far and away the easiest way to do nonblocking code in modern languages. It might even reach the extent that languages and/or frameworks that do not support it are going to be in real trouble as new user will expect it to be available. With so many different languages adopting the pattern, soon many may not have even been exposed to "the old ways" at all!
Last year, during the 2018 Mojolicious Advent Calendar, I introduced my Mojo::AsyncAwait library which was intended to address the immediate need for the Mojolicious community, based on the Mojolicious core promise module Mojo::Promise. It did rely on a "controversial" module (Coro) to accomplish its task, and therefore it was not a good candidate for all users.
Meanwhile, others in the Perl community were noticing as well. Paul Evans (LeoNerd) applied for and received a grant from The Perl Foundation to build a low-level async/await mechanism for his Future promise library. As that project has successfully culminated in Future::AsyncAwait on CPAN, the Mojolicious team has been engaging with Paul on a collaboration to allow Mojo::Promise to hook directly into it.
So without futher ado, the Mojolicious Core Team is very happy to announce that as of the most recent release of Mojolicious, async/await is now a built-in framework feature!