Issue chaining Futures

[mbrubeck]

There are some obstacles to using async/await without the alloc crate. On targets with core plus alloc it should be easier, I think. There are some relevant links in this thread:

Using async/await for automation sequences in embedded systems?

Something that happens a lot in embedded systems is to represent a particular process/sequence (e.g. a calibration sequence) using a state machine which gets polled to completion. This sounds almost exactly like the definition of Futures. For example, I could imagine wanting to write something like this: /// Find out the total travel distance along a particular axis. async fn calibrate_axis(axis: &mut Axis, front: &InputPin, back: &InputPin) -> Result<f32, Fault> { // first, move to the rear…