Flutter load file

We are in need of a library or class for Flutter WEB that allows us to upload a file to Amazon S3 using the PUT method. It is necessary to be able to have an update of the uploaded data, to be able to show in an upload the progress to the user. This is not possible with the DIO library nor with the HTTP MULTIPARTFILE methods. The HTTP navita library allows it but blocks the user interface. Important it has to work for FLUTTER WEB.