You’re better off with an asynchronous result stream, which is equivalent in power but much easier to reason about. C#’s got IAsyncEnumerable, I know that Rust is working on designing something similar. Even then, it can be hard to analyse the behaviour of multiple levels of asynchronous streams and passing pieces of information from the top level to the bottom level like a tag is a pain in the neck.
Generally, I prefer the coroutine/generator style, it is more explicit and straightforward syntax-wise. More importantly, it decouples operation execution from chaining. A function that emits multiple values in sync/async shouldn't be responsible for running the next function in the pipeline directly. It's better when the user of the interface has direct control over what function is run over which values and when, particularly for parallelizing pipelines.
I do understand that Rama builds such a syntax on top of CPS, and a compiler that implements generators has a similar execution model (perhaps an explicit state-machine rather than leveraging the function stack to do the same thing implicitly).