[steveklabnik]

> If those platform crates are just backends for libc (or similar to libc),

They're not, they're to the specific platform's APIs. The libc crate is a package that targets libc on every platform.

> Having to use proc-macro2+quote+syn for macros feels wrong, considering it's a language feature.

In order to ship procedural macros as a feature, they're pretty minimal. There's a tradeoff here; others could be chosen, but weren't for good reasons.

> Having to pull in 4 crates for pinning also seems wrong.

This is covered by https://news.ycombinator.com/item?id=24730280; that is, it's a transitive dependency issue.

> The async I/O feels like definite bloat.

Really depends, network calls are a textbook use-case for async I/O. And there's so many futures crates specifically so that you can only depend on the bits you need.