* @param {function} onLoad A function to be called after loading is successfully completed. The function receives loaded Object3D as an argument.
* @param {function} [onFileLoadProgress] A function to be called while the loading is in progress. The argument will be the XMLHttpRequest instance, which contains total and Integer bytes.
* @param {function} [onError] A function to be called if an error occurs during loading. The function receives the error as an argument.
* @param {function} [onMeshAlter] Called after worker successfully delivered a single mesh
* @param {function} [onMeshAlter] Called after every single mesh is made available by the parser