title: How Can I return a specific attribute using MarkerClusterGroup in Leaflet?
body: <p>In leaflet there is a an extension called : Leaflet.markercluster
  In this extension, there is a function called markerClusterGroup that clusters and returns the count of multiple Markers (points).
  see example : <a href="https://leaflet.github.io/Leaflet.markercluster/example/marker-clustering-realworld-maxzoom.388.html" rel="nofollow noreferrer">Here</a>.</p>
  
  <p>In my example I'm doing the same thing for my polygons centroids, that I calculated using turf. Each of my polygon has an attribute "Inhabitants" which represents the total inhabitants in the polygon. (<a href="http://leafletjs.com/examples/choropleth/example.html" rel="nofollow noreferrer">this looks like the example i'm working on</a>)</p>
  
  <p>The method markerClusterGroup returns the count of centroids in my example. Can I modify the method to modify the returned value into an aggregation of inhabitants ? If no, is there any library you know of capable of aggregating polygons on a specific attribute ?</p>