Structured per-record failure, fired once per failed record (in addition to
the human-readable PushCallbacks.onError lines). Use this to build a
machine-readable error list.
Called when a directory finishes. changed is true when the directory had any
create/update/delete/error, letting the UI highlight it vs. dim a pure no-op.
Structured per-record failure, fired once per failed record (in addition to the human-readable PushCallbacks.onError lines). Use this to build a machine-readable error list.