onReaderReady property
Called once when the native reader first reports content on screen.
This is a best-effort, per-platform signal, not a paint callback. Android fires it from the navigator's resource-loaded callback; iOS fires it from the first navigator location change. If the native navigator never reports either, this is never called.
The argument tells whether this native reader reports taps through onNativeTap. Readers that do not (PDF, comics) leave tap classification to the Flutter pointer observer.
Implementation
final void Function(bool nativeTapFeedback) onReaderReady;