Upload writeStream

[steffanhalv]

.uploadSession should return a write stream instead of / or in addition to having a callback.

This will make it easier to work with piping of readStreams, ex. to integrate with multer.

[dkatavic]

Hi @steffanhalv , are you still interested in building this

[steffanhalv]

Sorry, it already works. Only thing remains is the e2e test which I dont have time for.

[dkatavic]

That is cool, I will try to make time for it during the holidays 👍 . Thanks for contributing :)