import { Controllable, ControllerPullListener } from '@johngw/stream/sources/Controllable';
/**
 * A ControllableStream is ReadableStream that can have chunks
 * queued to from an external source.
 *
 * @group Sources
 * @example
 * Queuing items externally.
 *
 * ```
 * const controller = new ControllableStream<number>()
 * controller.enqueue(1)
 * controller.enqueue(2)
 * controller.enqueue(3)
 * controller.close()
 * ```
 *
 * Registering pull subscribers externally.
 *
 * ```
 * const controller = new ControllableStream<number>()
 * let i = -1
 * controller.onPull(() => ++i)
 * ```
 */
export declare class ControllableStream<T> extends ReadableStream<T> implements Controllable<T> {
    #private;
    constructor(strategy?: QueuingStrategy<T>);
    get desiredSize(): number | null;
    /**
     * Register a pull subscriber.
     *
     * @remark
     * When the stream is ready to pull it will pull from all
     * subscribers until the desired size has been fulfilled.
     */
    onPull(pullListener: ControllerPullListener<T>): () => void;
    error(error?: unknown): void;
    enqueue(chunk: T): void;
    close(): void;
}