declare class Queue<T> {
    private back?;
    private front?;
    private length;
    private readonly lowWaterMark;
    private readonly highWaterMark;
    constructor(lowWaterMark?: number, highWaterMark?: number);
    /**
     * Put at back
     */
    enqueue(data: T): void;
    /**
     * Alias of `enqueue`
     */
    push(data: T): void;
    /**
     * Pop from front
     */
    dequeue(): T | undefined;
    /**
     * Alias of `dequeue`
     */
    shift(): T | undefined;
    /**
     * Return data from front but keep it in queue.
     */
    peek(): T | undefined;
    readonly size: number;
    isEmpty(): boolean;
    aboveHighWaterMark(): boolean;
    underLowWaterMark(): boolean;
}
export { Queue };