If the problem that this is trying to solve is that `postMessage` is slow and you can't transfer slices of arrays, then perhaps they should solve it by speeding

If the problem that this is trying to solve is that `postMessage` is slow and you can't transfer slices of arrays, then perhaps they should solve it by speeding up `postMessage` and making array slicing cheap? Forcing a shared-memory concurrency model into JavaScript seems like a bit of an overreaction.