Part of my work involves the braid HTTP spec. Braid uses a custom server-sent events like protocol sent over long lived HTTP connections. I spent about a week trying to get this working using rust & actix. My code became mired in complex lifetimes, crazy iterators, Pin, async and Futures. Hundreds of lines of code later, I gave up and rewrote the whole thing in an hour or two, in about 30 lines of javascript.

The whole experience was so bad I've sworn off using async rust entirely until a few more features land. Thankfully, apparently there GAT lands next release - although its not clear to me if it'll work for futures yet, or if thats a later goal.

I love rust. But, wow.