/// <reference types="node" />
import { Writable } from "stream";
export declare type FileWriter = (offset: number, buffer: Buffer) => Promise<void>;
export declare class FileWriteStream extends Writable {
    private maxWriteChunkLength;
    private fileWriter;
    private _bytesWritten;
    get bytesWritten(): number;
    constructor(maxWriteChunkLength: number, fileWriter: FileWriter);
    _write(chunk: Buffer, encoding: any, callback: any): void;
}