Closes #2359 This PR switches away from `Image.decode()` to use the older method of `Image.onload` this method is more reliable for large or numerous images due to a chromium bug around decode. @HxShard provided a great codesandbox illustrating the issue https://codesandbox.io/s/happy-gagarin-j1vjr ## Changes: - Creates a new Future type for working with native Promises' resolve/reject at any time - Creates a new Semaphore type that can limit async calls in between `enter` and `exit` - Fixes a small clock schedule bug as well