For stageRunners with caching, find the next unexecuted stage.

For stageRunners with caching, find the next unexecuted stage.

stageRunner_next_stage()

Value

a character stage key giving the next unexecuted stage. If all stages have been executed, this returns FALSE. If the stageRunner does not have caching enabled, this will always return the first stage key (`'1'`).