Existing implementations of the resumable upload draft

Dear working group,

last month Jonathan Flat and Guoye Zhang already shared their
implementations for the resumable upload draft on this mailing list. I just
compiled it alongside with other existing implementations into one
repository at https://github.com/tus/draft-example.

It includes a list of servers and clients, instructions on how to use them,
sample code, and a table showing the interoperability between these
projects. In total, there are clients for iOS, browsers and the command
line. Servers are written in Swift, Go and .NET.

I hope that this helps to test and validate our draft as well as to ensure
that we all on the same page when working on the draft. Feel free to let me
know if you have any feedback or other implementations!

Best regards
Marius