Support blockwise transfer

[ShadowJonathan]

Title, we require this for ruma/lb#3, RFC for this is here

[martindisch]

I haven't planned on adding it, but it looks like a neat project you're working on. If you manage to pull it off in your fork and would like to upstream it later on, feel free to let me know.

[ShadowJonathan]

This is definitely something we'll upstream once we got it working 👍

[martindisch]

In the meantime somebody went ahead and implemented RFC7959, you can check it out in #21. I'm assuming you have already solved your particular problem anyway, so I'm closing this.