Please don't pull in wasm dependencies (via gloo-timers) on non-wasm platforms

[joshtriplett]

async-std with the unstable feature enabled pulls in various wasm-specific dependencies via the gloo-timers dependency of futures-timer, even on non-wasm platforms. This adds quite a few dependencies, and shows up when building tide.

[yoshuawuyts]

@joshtriplett agreed; we should fix that.

[e00E]

When I looked into this I was confused why this happens because in Cargo.toml it looks like the features are separated per target. I think it is related to rust-lang/cargo#1197 .

[jbr]

Possible fix at #864 doesn't rely on target-specific features and switches to a wasm feature, which would be semver-major for wasm users.

As far as I can tell, this issue also ends up interfering with the alloc feature

[Fishrock123]

See also this older duplicate issue: #823

[dignifiedquire]

fixed on master

[K4rakara]

gloo-timers is still enabled by default, thus pulling in all of the wasm dependencies unless you go out of your way to use default-features = false and all the other features manually.