import type { NeedleXRSession } from "./NeedleXRSession.js";
export declare type XRSessionEventArgs = {
    session: NeedleXRSession;
};
/**
 * Add a listener for when an XR session starts
 * This event is triggered when the XR session is started, either by the user or by the application before all other XR start events
 * @param fn The function to call when the XR session starts
 * @example
 * ```js
 * onXRSessionStart((evt) => {
 *   console.log("XR session started", evt);
 * });
 * ```
 */
export declare function onXRSessionStart(fn: (evt: XRSessionEventArgs) => void): void;
/**
 * Remove a listener for when an XR session starts
 * @param fn The function to remove from the listeners
 * @example
 * ```js
 * const myFunction = (evt) => {
 *  console.log("XR session started", evt);
 * };
 * onXRSessionStart(myFunction);
 * offXRSessionStart(myFunction);
 * ```
 */
export declare function offXRSessionStart(fn: (evt: XRSessionEventArgs) => void): void;
/**
 * Add a listener for when an XR session ends
 * This event is triggered when the XR session is ended, either by the user or by the application before all other XR end events
 * @param fn The function to call when the XR session ends
 * @example
 * ```js
 * onXRSessionEnd((evt) => {
 *    console.log("XR session ended", evt);
 * });
 * ```
 */
export declare function onXRSessionEnd(fn: (evt: XRSessionEventArgs) => void): void;
/**
 * Remove a listener for when an XR session ends
 * @param fn The function to remove from the listeners
 * @example
 * ```js
 * const myFunction = (evt) => {
 *  console.log("XR session ended", evt);
 * };
 * onXRSessionEnd(myFunction);
 * offXRSessionEnd(myFunction);
 * ```
 */
export declare function offXRSessionEnd(fn: (evt: XRSessionEventArgs) => void): void;
/**
 * @internal
 * Invoke the XRSessionStart event
 * @param evt The XRSession event arguments
 */
export declare function invokeXRSessionStart(evt: XRSessionEventArgs): void;
/**
 * @internal
 * Invoke the XRSessionEnd event
 * @param evt The XRSession event arguments
 */
export declare function invokeXRSessionEnd(evt: XRSessionEventArgs): void;