_getVaoKey( attributes ) {

		let key = '';

		for ( let i = 0; i < attributes.length; i ++ ) {

			const attributeData = this.get( attributes[ i ] );

			key += ':' + attributeData.id;

		}

		return key;

	}
Computes the VAO key for the given index and attributes.

@private
@param {Array<BufferAttribute>} attributes - An array of buffer attributes.
@return {string} The VAO key.