How to implement GMUClusterRenderer in Swift
<p>I am using Google Maps API for iOS and want to use marker clustering utility. I figured out how to show clustered markers, but I would like to customize markers. Can someone explain how to set/change icon and title of each marker or clustered markers? An example code would be very helpful.</p>

<pre><code>class POIItem: NSObject, GMUClusterItem {
    var position: CLLocationCoordinate2D
    var name: String!

    init(position: CLLocationCoordinate2D, name: String) {
        self.position = position
        self.name = name
    }
}

class MyRenderer: NSObject, GMUClusterRenderer {
    var mapView: GMSMapView
    var clusterIconGenerator: GMUClusterIconGenerator
    var clusterManager: GMUClusterManager

    init(mapView: GMSMapView, clusterIconGenerator: GMUClusterIconGenerator, clusterManager: GMUClusterManager) {
        self.mapView = mapView
        self.clusterIconGenerator = clusterIconGenerator
        self.clusterManager = clusterManager
    }

    func renderClusters(clusters: [GMUCluster]) {

    }

    func update() {

    }
}
</code></pre>

<p>This is what I have so far. I don't know what to do with renderClusters and update functions.</p>