private static void setCharsetAutoDetectionReason(@NotNull VirtualFile virtualFile,
                                                    @Nullable("null if was not detected, otherwise the reason it was") AutoDetectionReason reason) {
    virtualFile.putUserData(CHARSET_WAS_DETECTED_FROM_BYTES, reason);
  }
private static void setCharsetAutoDetectionReason(@NotNull VirtualFile virtualFile,
                                                    @Nullable("null if was not detected, otherwise the reason it was") AutoDetectionReason reason)