onFallback property

void Function(Object error, StackTrace stack)? onFallback

Optional callback invoked when the fallback is used. Receives the error and stack trace from the primary.

Privacy note: The error object may contain PII (e.g. face template data or API response bodies). Do not log it in production or transmit it to external services without sanitization.

Implementation

final void Function(Object error, StackTrace stack)? onFallback;