Merge pull request #1152 from dbauszus-glx/mapview-render-complete

promise renderComplete from addLayer

lib/mapview/addLayer.mjs

@@ -36,5 +36,11 @@ export default async function (layers) {
     layer.display && layer.show();
   }
 
+  // Will resolve once the map has completed render.
+  this.renderComplete = new Promise(resolve => {
+
+    this.Map.once('rendercomplete', resolve)
+  })
+
   return layers;
 }