Mutation event filtering type information for scrolling. Note that mutation event filtering is only done on remove and update events, not on add events. The reason is because the properties which indicate the location of an added row are optional so it is not possible to guarantee that an add is not occurring inside the already iterated rowset. Type of 'global' indicates that this DataProvider globally filters mutation events. Type of 'iterator' indicates that this DataProvider filters events based on rows which have been fetched via fetch iteration. Type of 'none' indicates that this DataProvider does not filter mutation events.