export interface MountTicket {
    /** Withdraws a queued mount; a mount that already ran is unaffected. */
    cancel(): void;
}
export interface MountSchedulerOptions {
    /** Mounts admitted per frame before the rest queue. */
    budgetPerFrame?: number;
    /** Frame source; injected so the queue can be driven in tests. */
    requestFrame?: (callback: () => void) => void;
}
/** Urgency of a mount; smaller runs first. */
export declare const MOUNT_PRIORITY: Readonly<{
    /** The frame the designer is on, or is about to be: mounts as soon as it fits. */
    active: 0;
    /** In or near the viewport. */
    visible: 1;
    /** Everything else. */
    background: 2;
}>;
export declare const DEFAULT_MOUNTS_PER_FRAME = 3;
/** One editor's frame-mount budget: the queue of pending mounts and how many run per animation frame. */
export declare function createMountScheduler(): {
    configureMountScheduler: (options: MountSchedulerOptions) => void;
    resetMountScheduler: () => void;
    pendingMountCount: () => number;
    scheduleMount: (run: () => void, priority?: number) => MountTicket;
};
export type MountScheduler = ReturnType<typeof createMountScheduler>;