I had better luck with nickel.rs because it has an examples/ folder with quick recipes of most things you'd want to do.
Unfortunately it seems to be a common trend that Rust projects only provide API docs. While that can be useful I find more 'high level' docs much more helpful especially when you're new to the language and/or framework.
EDIT: Oh, and I've wanted a good way for Cargo to produce additional, non-API docs through a top-level "docs" directory, but haven't found the time to properly implement it yet :/
Some packages like Serde for example do provide higher level docs located with the API docs which can work fine.
https://www.techempower.com/benchmarks/#section=data-r12&hw=...
I'm not sure why this is - I've Googled to no avail - but it is rather worrying.
https://github.com/TechEmpower/FrameworkBenchmarks/blob/mast...
That said, I don't think that missing out on --release was the issue here, as far as I know, it has always been on.