Fix for scheduling recurrent functions while inside scheduled function #6307
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Dear @d-a-v,
I hope to have come up with a relatively small fix to Schedule that allows scheduling from inside already scheduled functions. I am using this with my CoopTask scheduling, without this patch, the sketch crashed, with it, it performs correctly. I don't see any reason for side-effects, like poorer performance. Memory use is minimally increased by the use of a recurrent_fn_t instance for rFirst instead of the previous pointer, but the logic looked cleaner to me when I began the patch, and I'd rather not change it back if there's no compelling reason.
Could you please review this?