The pieces in the order of the recording. An async iterable is asked for its next piece only when the job has room to send it.
The caller's transcription of one piece.
The sentence cut, and how the job runs.
text, the pieces' texts joined at their seams, after previousText when one is given; pieces, each
piece's outcome in order; seconds, the sum of the outcomes' seconds.
When a piece fails every attempt. The pieces before it have been reported to onPiece by
then, and no piece after it is reported.
The reason of options.signal, after interrupting a pending source read and awaiting pieces in flight.
The original source or onPiece error, after awaiting pieces in flight.
Transcribes the pieces; answers the whole text and each piece's outcome.