WASM support

This issue is an attempt to gather information relating to WASM support for rust-libp2p as well as serve as somewhat of a tracking / discussion issue.

Transports

The general approach that we've been taking for transports it to use the web-sys bindings and code against those directly. This allows us to stay in Rust land without having to write any JS. Additionally, the acceptance criteria for any further transport is that they are integrated in the interop-test suite.

Testing

We have additional tests that go beyond the interop suite in the wasm-tests directory: https://github.com/libp2p/rust-libp2p/tree/master/wasm-tests

- [x] https://github.com/libp2p/rust-libp2p/pull/4015
- [x] https://github.com/libp2p/rust-libp2p/pull/4248
- [ ] https://github.com/libp2p/rust-libp2p/issues/3611
- [ ] https://github.com/libp2p/rust-libp2p/issues/4389
- [ ] Remove `libp2p-wasm-ext` in the next breaking release
- [ ] https://github.com/libp2p/rust-libp2p/issues/4509

Previous Implementations of WASM libp2p

• https://github.com/paritytech/smoldot
• https://github.com/iotaledger/identity.rs
• https://github.com/sireliah/wasm-p2p-experiment

Start by reviewing the unchecked task links, the interop-test suite, and the additional tests in wasm-tests. Check the remaining work around libp2p-wasm-ext and the referenced issues before choosing a specific task; done is completing one scoped item with the relevant interoperability or WASM tests passing.