[@types/leaflet.markercluster] add missing chunkInterval option (#34030)

* leaflet.markercluster: add missing chunkInterval option

* leaflet.markercluster: bump version number to 1.4

types/leaflet.markercluster/index.d.ts

@@ -1,4 +1,4 @@
-// Type definitions for Leaflet.markercluster 1.0
+// Type definitions for Leaflet.markercluster 1.4
 // Project: https://github.com/Leaflet/Leaflet.markercluster
 // Definitions by: Robert Imig <https://github.com/rimig>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
@@ -115,6 +115,12 @@ declare module 'leaflet' {
         * Time delay (in ms) between consecutive periods of processing for addLayers. Default to 50ms.
         */
         chunkDelay?: number;
+
+        /*
+        * Time interval (in ms) during which addLayers works before pausing to let the rest of the page process.
+        * In particular, this prevents the page from freezing while adding a lot of markers. Defaults to 200ms.
+        */
+        chunkInterval?: number;
     }
 
     class MarkerClusterGroup extends FeatureGroup {

types/leaflet.markercluster/leaflet.markercluster-tests.ts

@@ -26,7 +26,8 @@ markerClusterGroupOptions = {
         return icon;
     },
     chunkedLoading: false,
-    chunkDelay: 100
+    chunkDelay: 100,
+    chunkInterval: 200,
 };
 
 markerClusterGroupOptions.iconCreateFunction = (cluster: L.MarkerCluster) => {