Enum Effect 

pub enum Effect {
    Focus(u64),
    Scroll(u64, ScrollTo),
    Sheet(u64, SheetTo),
    Spawn(Box<dyn FnOnce() -> Option<Callback> + Send>),
    After(Duration, Callback),
    Async(Task),
}

A request to the shell that is not a widget: something to do once.

Variants

Focus(u64)

Focus the widget wrapped in keyed(key, …) — the hash of its key.

Scroll(u64, ScrollTo)

Move the scroll region named by the hash of a key.

Sheet(u64, SheetTo)

Move the sheet named by the hash of a key.

Spawn(Box<dyn FnOnce() -> Option<Callback> + Send>)

Run this on another thread; if it answers with a callback, that callback runs on the interface’s thread.

After(Duration, Callback)

Run this callback after a delay.

Async(Task)

Await this; if it answers with a callback, that callback runs on the interface’s thread.