Add support for WASM targets

[Luthaf]

This PR adds support for Monotonic on both WASM targets: wasm32-unknown-unknown (web) and wasm32-wasi (wasi). On the web, it uses window.performance.now(); and on wasi it uses clock_time_get with a monotonic clock.

I did not ran the tests on these targets, but I'll try to do so in the next few days.

[tobz]

At first glance, this looks reasonable to me. I'll try to do a full review on it in the next few days. The cfg conditionals are starting to get a bit hairy and I want to make sure things are 👌🏻 😅

[Luthaf]

The cfg conditionals are starting to get a bit hairy and I want to make sure things are 👌🏻 😅

Yeah, wasm being available on both web and wasi do not help here ...

[Luthaf]

I cleaned up the code as suggested in the review, and added support to run the tests.

running tests for wasm32-wasi

# install wasmtime
curl https://wasmtime.dev/install.sh -sSf | bash
export CARGO_TARGET_WASM32_WASI_RUNNER="wasmtime run"
cargo test --target wasm32-wasi

running tests for wasm32-unknown-unknown

# install wasm-pack
curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh 
# run tests on firefox
wasm-pack test --firefox --headless
# run tests on chrome
wasm-pack test --chrome --headless

# run tests on node (require commenting out the configure_wasm_tests module in lib.rs)
# this currently fails with ReferenceError: Window is not defined due to 
wasm-pack test --node

[tobz]

For my own curiosity: does std::thread::spawn not work at all on WASM?

[Luthaf]

At least currently, yes. There are proposals to add threading to WASM, both in browsers and WASI, but they are still in early stage.

[Luthaf]

I've added some documentation on accuracy, let me know if there is a better way to do express these limitations

[tobz]

@Luthaf Changes look good to me, just need to run cargo fmt and this should be set to merge.

stale

[tobz]

@Luthaf Sorry for the delay here. [email protected] is now released and contains your PR.

Thanks again for your contribution! 🌮

[Luthaf]

thanks a lot for the release!