A variant on
Producer which does not know its exact length or
cannot represent it in a
usize. These producers act like
ordinary producers except that they cannot be told to split at a
particular point. Instead, you just ask them to split ‘somewhere’.
Producer could extend this trait; however, it
does not because to do so would require producers to carry their
own length with them.)
The type of item returned by this producer.
Split midway into a new producer if possible, otherwise return
Iterate the producer, feeding each element to
stop when the folder is full (or all elements have been consumed).