import { SLLQueue } from '@proficient/ds';
export declare class SLLQueueExtended<E> extends SLLQueue<E> {
    /**
     * Dequeues the first `itemCount` items into an array.
     *
     * @param itemCount - The number of items to dequeue.
     * @returns The array of dequeued items.
     * @throws {@link IllegalArgumentError} Thrown if `itemCount` is invalid.
     */
    dequeueFirst(itemCount: number): E[];
}