import { EngineAction, EngineActions } from './EngineActions';
import { EngineEvent, EngineEventContext } from './EngineEvent';
/**
 * Describes the Signature that a Middleware for handling Engine events should have.
 */
export declare type MiddlewareCallback<TPayload extends Record<string, any>> = (engineEvent: EngineEvent, context?: EngineEventContext) => Promise<EngineAction<TPayload> | EngineActions<TPayload> | void> | EngineAction<TPayload> | EngineActions<TPayload> | void;
export declare const middlewareEventTag = "middlewareEventTag";