This plugin makes more async await code works in Unity WebGL. For instance all of following will work:
task.ContinueWith(t => Debug.Log("ContinuWith works"));
Task.Run(() => Debug.Log("Task.Run works!"));
await task.ConfigureAwait(false);
await Task.Delay(1000);
This plug-in use IIl2CppProcessor callback to hijack mscorelib and change some methods implementation. It change ThreadPool methods that enqueue work items to delegate work to SynchronizationContext so all items will be executed in same thread. Also it patch Timer implementation to use Javascript timer functionality.
All tasks will be executed by just one thread so any blocking calls will freeze whole application. Basically it similar to async await behavior in Blazor.