/** Sequence of values designed to be extended that implements the full async generator protocol. */
export declare abstract class AbstractSequence<T, R, N> implements AsyncIterator<T, R, N>, AsyncIterable<T, R, N> {
    readonly [Symbol.toStringTag] = "Sequence";
    abstract next(value: N): Promise<IteratorResult<T, R>>;
    return(returnValue: R | PromiseLike<R>): Promise<IteratorResult<T, R>>;
    throw(reason: unknown): Promise<IteratorResult<T, R>>;
    [Symbol.asyncIterator](): AsyncIterator<T, R, N>;
}