How to get the location of an ink signature for digital signing

@Override
public void onDocumentLoaded(@NonNull PdfDocument document) {
    // `getAllAnnotationsOfType()` is a suspend function. `runBlocking()` waits for it to finish,
    // so run it on a worker thread.
    new Thread(() -> {
        try {
            List<? extends Annotation> inkAnnotations = BuildersKt.runBlocking(
                EmptyCoroutineContext.INSTANCE,
                (scope, continuation) -> document.getAnnotationProvider()
                    .getAllAnnotationsOfType(EnumSet.of(AnnotationType.INK), continuation));

            // This will return the first ink signature found in the document.
            for (Annotation inkAnnotation : inkAnnotations) {
                if (inkAnnotation.isSignature()) {
                    runOnUiThread(() -> digitallySignAtLocation(inkAnnotation.getBoundingBox()));
                    break;
                }
            }
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }).start();
}

@Override
public void onDocumentLoaded(@NonNull PdfDocument document) {
    super.onDocumentLoaded(document);
    document.getAnnotationProvider().addOnAnnotationUpdatedListener(new AnnotationProvider.OnAnnotationUpdatedListener() {
        @Override
        public void onAnnotationCreated(@NonNull Annotation annotation) {
            if (annotation instanceof InkAnnotation &&
                ((InkAnnotation) annotation).isSignature()) {
                // This will be called when the user adds a new ink signature.
                digitallySignAtLocation(annotation.getBoundingBox());
            }
        }

        @Override
        public void onAnnotationUpdated(@NonNull Annotation annotation) {

        }

        @Override
        public void onAnnotationRemoved(@NonNull Annotation annotation) {

        }

        @Override
        public void onAnnotationZOrderChanged(int pageIndex,
                                              @NonNull List<Annotation> oldOrder,
                                              @NonNull List<Annotation> newOrder) {

        }
    });
}

@Override
public void onDocumentLoaded(@NonNull PdfDocument document) {
    super.onDocumentLoaded(document);
    getPdfFragment().addOnAnnotationSelectedListener(new AnnotationManager.OnAnnotationSelectedListener() {
        @Override
        public boolean onPrepareAnnotationSelection(@NonNull AnnotationSelectionController controller,
                                                    @NonNull Annotation annotation,
                                                    boolean annotationCreated) {
            // You can return `false` to prevent the default annotation selection from happening.
            return true;
        }

        @Override
        public void onAnnotationSelected(@NonNull Annotation annotation, boolean annotationCreated) {
            if (annotation instanceof InkAnnotation &&
                ((InkAnnotation) annotation).isSignature()) {
                // This will be called when the user selects an ink signature.
                digitallySignAtLocation(annotation.getBoundingBox());
            }
        }
    });
}