import { ThroughSequence } from "./ThroughSequence.js";
/**
 * Sequence of values that inspects a source sequence of values as it iterates.
 * - Stores: first/last yielded value, returned value, whether iteration is done, the number of items that were iterated.
 *
 * @example
 * 	const watch = new InspectSequence(iterable);
 * 	for await (const next of capture) console.log("YIELDED", next);
 * 	console.log("FIRST", watch.first);
 * 	console.log("RETURNED", watch.returned);
 */
export declare class InspectSequence<T, R, N> extends ThroughSequence<T, R, N> {
    /** Get the number of results received by this iterator so far. */
    get count(): number;
    private _count;
    /** Is the iteration done? */
    get done(): boolean;
    private _done;
    /** The first yielded value (throws if the iteration yielded no values, i.e. `this.count === 0`). */
    get first(): T;
    private _first;
    /** The last yielded value (throws if the iteration yielded no values, i.e. `this.count === 0`). */
    get last(): T;
    private _last;
    /** The returned value (throws if the iteration is not done, i.e. `this.done === false`). */
    get returned(): R | undefined;
    private _returned;
    next(value?: N | undefined): Promise<IteratorResult<T, R | undefined>>;
    return(value?: R | undefined | PromiseLike<R | undefined>): Promise<IteratorResult<T, R | undefined>>;
    throw(reason?: unknown): Promise<IteratorResult<T, R | undefined>>;
    /** Capture a result. */
    private _inspect;
}