Browser support checklist

[albrow]

This issue serves as a way to track overall progress on WebAssembly/browser compatibility. A lot of progress has already been made. For example, we added WebAssembly support to pion/webrtc which will serve as the underlying mechanism for establishing a direct connection between two browser-based peers.

Here are the remaining tasks (including those already in progress):

• Reach general consensus on specification for WebRTC signaling protocol.
• Depending on where we land with the signaling protocol, we may need to add Wasm support to go-ws-transport. Browser peers would use the WebSocket transport to communicate with a signaler and then switch to the WebRTC transport with the desired peer after signaling is complete.
• Update go-libp2p-webrtc-direct to support direct browser-to-browser connections via the signaling protocol, or alternatively, create a new transport that supports them.
• Add Wasm support to go-libp2p-peerstore.
• Create Wasm-compataible peer discovery mechanism (likely either Kademlia DHT or Peer Exchange).
• Update BrowserFS to support special file descriptors 0, 1, and 2.
• Add WebAssembly support to go-leveldb, likely by using BrowserFS. Partial Wasm support (works in Node but not in browsers) has already been implemented.
• Implement JavaScript/TypeScript callback functions for interacting with 0x Mesh from the browser.
• Publish JavaScript/TypeScript package which is a wrapper around our callback functions and the Wasm bundle.

[albrow]

Closing this in favor of individual issues and a Milestone: https://github.com/0xProject/0x-mesh/milestone/2.