Marking files as complete without uploading them

Hi,

I’m writing a Preprocessor plugin that communicates with my own API before upload and understands which of the files that the user requests to upload already exist on the server.
The actual upload is done via the AwsS3Multipart plugin.

I couldn’t find a way to mark a file as completed so Uppy won’t try to upload it.
I tried following the advice on this Github issue, but it’s not working in the current version:

Would appreciate any leads on how to accomplish this with uppy currently.

Thanks!