import { Eventual, Logger, Mapper, Reducer, TryMapOptions } from '@graphprotocol/common-ts';
export interface TimerTaskContext {
    logger: Logger;
    milliseconds: number;
}
/**
 * Create an eventual that performs the work in the Reducer<number, U> function every `milliseconds` milliseconds.
 * The main difference between this and `timer(...).reduce(...)` is that this function will wait for the previous work to complete before starting the next one.
 *
 * @param milliseconds number
 * @param reducer Reducer<number, U>
 * @param initial U
 * @returns Eventual<U>
 */
export declare function sequentialTimerReduce<T, U>({ logger, milliseconds }: TimerTaskContext, reducer: Reducer<number, U>, initial: U): Eventual<U>;
/**
 * Create an eventual that performs the work in the Mapper<U> function every `milliseconds` milliseconds.
 * The main difference between this and `timer(...).tryMap(...)` is that this function will wait for the previous work to complete before starting the next one.
 *
 * @param milliseconds number
 * @param mapper Mapper<U>
 * @param options TryMapOptions
 * @returns Eventual<U>
 */
export declare function sequentialTimerMap<U>({ logger, milliseconds }: TimerTaskContext, mapper: Mapper<number, U>, options?: TryMapOptions): Eventual<U>;