import { Writable } from 'node:stream';
import type { HeaderStream } from '../../src/stream.js';
export declare class Sink extends Writable implements HeaderStream {
    #private;
    constructor();
    assertWriteHead(assertion: (statusCode: number, headers: any) => void): void;
    get content(): string;
    _write(chunk: Buffer, _encoding: BufferEncoding, callback: (error?: Error | null) => void): void;
}