[remram]

Honestly it still seems like a lot this way.

If those platform crates are just backends for libc (or similar to libc), why aren't they all folded in a single project? Having them as separate crates open the gate for supply-chain attacks without really allowing greater control or expressiveness. You are always going to pull all of them in, you are unlikely to ever use them directly, and they have no more impact on compilation than features.

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

Having to pull in 4 crates for pinning also seems wrong. This could easily be a single utility crate, and if you really need all this cruft to use Pin (a language feature) most of this should probably be in std.

The async I/O feels like definite bloat. Not only is that a lot of futures-* crates, but I know from first-hand experience that those tend to implement multiple versions of some primitives (like streams) that are incompatible.

[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.