Plan for enabling Wasm threads

[annevk]

From WebAssembly/design#1261:

In tc39/ecma262#1435 I detailed an approach the HTML community is planning on taking for reenabling ECMAScript's SharedArrayBuffer. This also affects Wasm if Wasm ever gets its own thread primitive (rather than building on top of workers and postMessage()) or some other high-resolution timer mechanism. Your input is most welcome.

[annevk]

You can now play with this in Firefox Nightly: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer/Planned_changes.

[annevk]

The HTML Standard now fully defines this. Firefox 79 implements it (shipping later this month). Chrome will migrate to it. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer/Planned_changes is still a useful high-level summary.

Feel free to close this.