Reconciles the two reports into one decision, per XEP-0260 §2.4.
The rules, and one interpretation this project has to pin down:
One side reports a candidate and the other an error → the candidate wins.
Both report → the higher priority candidate wins.
Equal priority → the XEP says "the candidate offered by the initiator is
used". A side always reports a candidate from its peer's list, so the
initiator-offered candidate is the one the responder reported. That is
the reading implemented here, and it is recorded in
docs/protocol-notes.md — the wording is ambiguous enough that an
implementation could plausibly do the opposite and deadlock on ties.
Both error → no bytestream; the caller falls back.
Reconciles the two reports into one decision, per XEP-0260 §2.4.
The rules, and one interpretation this project has to pin down: