private static PsiAnnotation markAsExternalAnnotation(@NotNull PsiAnnotation annotation) {
    annotation.putUserData(EXTERNAL_ANNO_MARKER, Boolean.TRUE);
    ((LightVirtualFile)annotation.getContainingFile().getViewProvider().getVirtualFile()).setWritable(false);
    return annotation;
  }
private static PsiAnnotation markAsExternalAnnotation(@NotNull PsiAnnotation annotation)