/**
 * Buffers the source stream chunks until `notifier` emits.
 *
 * @group Transformers
 * @example
 * ```
 * --a--b--c--d--e--f--g--h--i--|
 *
 * buffer(
 * --------B--------B--------B--|
 * )
 *
 * --------[a,b,c]--[d,e,f]--[g,h,i]-|
 * ```
 */
export declare function buffer<T>(notifier: ReadableStream<unknown>, maxBuffer?: number): TransformStream<T, T[]>;