import { AsyncSequence } from "../../sequency";
export declare class IndexOfFirst {
    /**
     * Returns the zero-based index of the first element matching the given `predicate` or -1 if no element matches
     * the predicate.
     *
     * @param {(value: T) => Promise<boolean> | boolean} predicate
     * @returns {Promise<number>}
     */
    indexOfFirst<T>(this: AsyncSequence<T>, predicate: (value: T) => Promise<boolean> | boolean): Promise<number>;
}