It would be nice to be able to redirect stdin/stdout/stderr for individual tasks.

[Thiez]

As the title says, this would be a nice feature to have, and could be a part of the new I/O design (#4248).
One possible application would be buffering stdout/stderr of the tests so that any output can appear without being mixed with output from other tests. I'm sure other (useful) applications exist, such as discarding unwanted output from a task.

[toddaaro]

Not sure if this will make it in, but it is an idea worth considering as this whole API is changing a lot. Tagged with runtime.

[catamorphism]

Would be nice; not a milestone blocker.