export declare type ProducerResult<T> = T | Promise<T> | AsyncIterable<T>;
export interface ProducerFn<T, R> {
    (this: T): ProducerResult<R>;
}
export declare function produce<T, R>(thisState: T, fn: ProducerFn<T, R>): AsyncIterable<R>;
export declare function produceWithMutatingThis<T extends object>(fn: ProducerFn<T, T>, initialThis?: T): AsyncIterable<T>;