block state updates while command is in flight

Currently the user needs to defend against getting an unrelated state update originating from a network event immediately after invoking a command:
```typescript
let thingDone = false
for await (const state of machine) {
if (state.is(SomeState) && !thingDonw) {
state.cast().commands()?.doTheThing()
thingDone = true
}
}
```
It would be nicer and more intuitive if the next loop iteration was guaranteed to contain the information that was published via the `doTheThing` action (which usually will be reflected in transitioning to a new state, but might also just add something to the current state).

Start by tracing the async iteration shown in the issue, especially the `for await (const state of machine)` loop and the `doTheThing` command. Determine where command publication and subsequent state delivery are coordinated. Done means the next loop iteration reliably includes the command's published information without requiring the caller's `thingDone` guard.

Written by the indexing model from the issue text.