import { Operator, Producer, ExtractContent } from './types';
export declare function sampleCombine<T, U extends [...Producer<any>[]]>(...sources: U): Operator<T, Prepend<T, ExtractContent<U>>>;
export declare function sample<T, U>(source: Producer<U>): Operator<T, U>;
export declare function sampleWith<T, R, U>(f: (data: T, sampled: R) => U, sample: Producer<R>): Operator<T, U>;
declare type Prepend<U, T extends [...any[]]> = ((u: U, ...rest: T) => any) extends (...res: infer X) => any ? X : never;
export {};