/// <reference types="node" />
import * as EventEmitter from 'events';
import { CognacSourceInterface } from './source';
import { CognacContext } from './context';
export declare class CognacPipeline<T> extends EventEmitter {
    source: CognacSourceInterface<T>;
    private middleware;
    constructor(source: CognacSourceInterface<T>);
    private exec;
    start(): Promise<void>;
    stop(): Promise<void>;
    add(fn: (context: CognacContext<T>) => any): void;
    sink(fn: (context: CognacContext<T>) => any): void;
}