/**
 * Event Bus
 *
 * Internal event routing between state broadcaster middleware and SSE streams.
 */
import { EventEmitter } from "events";
import type { StateChangedEvent, ExecutionLifecycleEvent } from "../types.ts";
/**
 * Create an event bus for internal routing
 *
 * Events flow:
 *   State Broadcaster Middleware -> EventBus -> SSE Route Handler
 */
export declare function createEventBus(): EventEmitter;
/**
 * Subscribe to state change events
 */
export declare function onStateChanged(bus: EventEmitter, handler: (event: StateChangedEvent) => void): () => void;
/**
 * Subscribe to execution lifecycle events
 */
export declare function onExecutionLifecycle(bus: EventEmitter, handler: (event: ExecutionLifecycleEvent) => void): () => void;
/**
 * Emit a state change event
 */
export declare function emitStateChanged(bus: EventEmitter, event: StateChangedEvent): void;
/**
 * Emit an execution lifecycle event
 */
export declare function emitExecutionLifecycle(bus: EventEmitter, event: ExecutionLifecycleEvent): void;
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