1. @DomName('ExtendableEvent.waitUntil')
  2. @DocsEditable()
  3. @Experimental()
void waitUntil(Object value)

Source 

@DomName('ExtendableEvent.waitUntil')
@DocsEditable()
@Experimental() // untriaged
void waitUntil(Object value) =>
    _blink.BlinkExtendableEvent.instance.waitUntil_Callback_1_(this, value);