/**
 * A basic, dependency-free event emitter implementation for internal library use.
 */
type EventHandler = (payload?: any) => void;
export declare class SimpleEventEmitter {
    private listeners;
    /**
     * Subscribes a handler function to an event.
     * @param event - The name of the event to subscribe to.
     * @param handler - The function to call when the event is emitted.
     */
    on(event: string, handler: EventHandler): void;
    /**
     * Unsubscribes a specific handler function from an event.
     * @param event - The name of the event to unsubscribe from.
     * @param handler - The handler function to remove.
     */
    off(event: string, handler: EventHandler): void;
    /**
     * Emits an event, calling all subscribed handlers with the provided payload.
     * Handlers are called synchronously in the order they were added.
     * Includes basic error handling for individual handlers.
     * @param event - The name of the event to emit.
     * @param payload - Optional data to pass to the event handlers.
     */
    emit(event: string, payload?: any): void;
    /**
     * Removes all event handlers for a specific event, or all handlers for all events.
     * @param event - Optional: The name of the event to clear listeners for. If omitted, all listeners for all events are removed.
     */
    removeAllListeners(event?: string): void;
}
export {};