getAttributesData( attributes ) {

		const attributesData = {};

		for ( const name in attributes ) {

			const attribute = attributes[ name ];

			attributesData[ name ] = {
				version: attribute.version
			};

		}

		return attributesData;

	}
Returns an attribute data structure holding the attributes versions for
monitoring.

@param {Object} attributes - The geometry attributes.
@return {Object} An object for monitoring the versions of attributes.