import type { IStream, ITime } from '../types.js';
/**
 * Emits the target time value at that time, then ends.
 * If the target time is strictly in the past, ends without emitting.
 *
 * at(3) when current=1:  --3|   (waits 2 units)
 * at(3) when current=5:  |      (time passed, ends immediately)
 * at(0) when current=0:  0|     (emits immediately)
 */
export declare const at: (time: ITime) => IStream<ITime>;