Add ability to upload files

[ipeychev]

There is some odd issue with Magnet and uploading forms. To explain it, I created two examples: uploading files with and without Magnet. They are practically the same, but the one with Magnet throws "stream ended unexpectedly" error :/

How to reproduce:

1. Download and unzip this zip file. It contains two examples for uploading files - with and without Magnet.
2. Do "npm install" in each of the directories and then "npm run dev". Open the browser on "http://localhost:3000" and try to upload a file.

Expected result in the Magnet demo:
File to be uploaded successfully.

Actual result:
A "stream ended unexpectedly" exception is being thrown.

Note: there is sync and async version in Magnet example. Both throw same error. By defaut the demo works with the sync version.

For reference, the original example (without Magnet) I copied from here.

[zenorocha]

Is this still valid?

[ipeychev]

It is, but it is not important. I believe no one is using this functionality and we can move it to backlog or even close it. If needed, we can reopen it.

[zenorocha]

Thanks @ipeychev!

[pragmaticivan]

If that's valid and still happens, I think we should not close the issue. Instead, we can just remove the labels.

[zenorocha]

Updated