Option to ignore hidden markers

[johnkamau]

The previous marker clusterer had an option to ignoreHidden, which I presume was a check for whether the marker was visible. With the new AdvancedMarkerElements, the only way to hide them is to set the map value to null, which hides them from the map.

Would it be possible for the markerClusterer to have an option that would check if the map value is null and thus not cluster those that are essentially hidden? at the moment all markers are clustered, regardless of whether they are visible or not.