Pim
UploadFilesOperation should have little to do with creating a new `URLSession` and its delegate method. Ideally `APIClient` should have a method to create a new `APIClient` and accept a closure...
Currently the `Authorizer` class only stores a bearer and adds it to a given request. It should be responsible for the actual authentication and could also handle the case of...
Add the ability to create a transfer with in-memory objects like images. Any object that can be represented as `Data` should be able to be added to a transfer