CastingTrait
constCastingTrait:Trait<{ability:string;request:number;secondsLeft:number;target:Entity|null; }>
A cast started and not released: the ability, its target, null for an
area cast, the seconds of wind-up left, and the page’s request id. What it holds back is each resource’s reserved.
Predicted: her page starts it on the press and winds it down as the
room does, and every page sees it.