@s4nchez The end user doesn't have to feel anything, if the inner implementation is using Coroutines or not, like
Ktor.io. Vert.x on the other hand has event loop thread pool that can be turned into a Coroutine Context and the concept of a çoroutine Verticle instead of a regular one (which in http4k terms would be a set of suspend functions for the end user as opt-in for using Coroutines for request handlers), it could a bit of the best of both worlds...