Possibility to stop upload in preprocessor

We offer an customization point to implement a File Upload Preprocessor, see [1], on behalf of preprocessing (e.g. sanitizing) uploaded files before they are stored in the repository.

However, there is no possibility to stop the upload and to show a message to the user, similar to what can be done in the validation phase (which takes actually place before to preprocessing), see [2].

Client use case:

We implemented a custom preprocessor for asset uploads to remove metadata from the files. But in case of an error when removing the data there is no chance to prevent the original file from being published.

What we want is to stop the upload process and show an error to the author in the cms.

[1] https://xmdocumentation.bloomreach.com/library/concepts/images-and-assets/implement-a-custom-file-upload-preprocessor.html
[2] https://xmdocumentation.bloomreach.com/library/concepts/editor-interface/image-and-asset-upload-validation.html