import { Pipeline } from '../pipeline.js';
import type { TransformOptions, TransformTyped } from '../stream.model.js';
/**
 * Allows to "fork" away from the "main pipeline" into the "forked pipeline".
 *
 * Correctly keeps backpressure from both "downstreams" (main and forked).
 *
 * @experimental
 */
export declare function transformFork<T>(fn: (pipeline: Pipeline<T>) => Promise<void>, opt?: TransformOptions): TransformTyped<T, T>;