context object with tile as third argument argument to fetch function

src/GeoJson.js

@@ -75,14 +75,15 @@ ms.geoJson = function(fetch) {
     var g = tile.element = ms.svg("g");
 
     var tileProj = proj(tile);
+    var context = {zoom: tile.zoom, row: tile.row, column: tile.column};
 
     tile.features = [];
 
     function update(data) {
       var updated = [];
 
       /* Fetch the next batch of features, if so directed. */
-      if (data.next) tile.request = fetch(data.next.href, update);
+      if (data.next) tile.request = fetch(data.next.href, update, {context: context});
 
       if (geoJson.tile() && tileBackground) {
         var tileSize = geoJson.map().tileSize();
@@ -100,7 +101,7 @@ ms.geoJson = function(fetch) {
     }
 
     if (url != null) {
-      tile.request = fetch(typeof url == "function" ? url(tile) : url, update);
+      tile.request = fetch(typeof url == "function" ? url(tile) : url, update, {context: context});
     } else {
       update({type: "FeatureCollection", features: features || []});
     }

src/TopoJson.js

@@ -52,13 +52,13 @@ ms.topoJson = function(fetch) {
     return features;
   };
 
-  var topoToGeo = function(url, callback) {
+  var topoToGeo = function(url, callback, options) {
     return fetch(url, function(topology) {
       callback({
         type: "FeatureCollection",
         features: topologyFeatures(topology)
       });
-    });
+    }, options);
   };
 
   var topoJson = ms.geoJson(topoToGeo);