Babylon.js/src/Instrumentation/timeToken.ts

import { Nullable } from "../types";
/**
 * @hidden
 **/
export class _TimeToken {
    public _startTimeQuery: Nullable<WebGLQuery>;
    public _endTimeQuery: Nullable<WebGLQuery>;
    public _timeElapsedQuery: Nullable<WebGLQuery>;
    public _timeElapsedQueryEnded = false;
}