import { Stream } from '@motorcycle/types';
/**
 * Deliver the most recently seen event to each new observer the instant it
 * begins observing. A held stream is always multicast.
 *
 * Given an input stream:
 *
 * ```
 * stream:    -a---b---c---d->
 * ```
 *
 * observers which begin observing at different times will see:
 *
 * ```
 * observer1: -a---b---c---d->
 * observer2:    a-b---c---d->
 * observer3:           c--d->
 * ```
 *
 * @name hold<A>(stream: Stream<A>): Stream<A>
 *
 * @example
 * import { createDocumentDomSource events } from '@motorcycle/dom'
 * import { drain, hold, map } from @motorcycle/stream'
 *
 * const doc = createDocumentDomSource(now(document))
 *
 * // start holding on first subscription
 * const click$ = hold(map(e => ({ x: e.clientX, y: e.clientY }), events('click', doc)))
 *
 * // hold the latest event even before the first subscription
 * drain(click$)
 */
export declare function hold<A>(stream: Stream<A>): Stream<A>;