/**
 * Adds a counter representing the amount of chunks
 * received thus far.
 *
 * @group Transformers
 * @example
 * ```
 * --a----------------------b-------|
 *
 * withCounter()
 *
 * --{chunk:'a',counter:0}--{chunk:'b',counter:1}-|
 * ```
 */
export declare function withCounter<T>(start?: number): TransformStream<T, {
    chunk: T;
    counter: number;
}>;