Reactive

public class System.Reactive.Reactive : System.Any
{
    static field depth: i32
    static field pending: System.List<System.Reactive.Effect?>
    // The effect running now (what a Source being read should track), or null.
    static field Current: System.Reactive.Effect?
    // Runs `body` now, and again whenever a reactive value it read changes.
    static method Watch(body: func<> : void) -> System.Reactive.Effect
    // Runs `body`; the effects its changes trigger run once each when it is done.
    static method Batch(body: func<> : void) -> void
    // Runs an effect now, or once at the end of the batch in progress.
    static method Schedule(effect: System.Reactive.Effect) -> void
    // Computes a lazy effect now, also inside a batch: a read of a computed sees the current values, not what it
    // kept before the batch changed something it depends on. One scheduled in the batch is done with (it does
    // not go stale again when the batch ends).
    static method Refresh(tracker: System.Reactive.Effect) -> void
    static method Flush() -> void
}