Get local box metadata in remote box

lib/vagrant/box/remote.rb

@@ -34,6 +34,7 @@ module Vagrant
             "Remote client is required for `#{self.class.name}'"
         end
         @client = client
+        @metadata = client.box_metadata
       end
 
       def destroy!

plugins/commands/serve/client/box.rb

@@ -52,10 +52,16 @@ module VagrantPlugins
           return machines
         end
 
-        # @return [Hash] metadata
+        # @return [Hash] box metadata
+        def box_metadata
+          res = client.box_metadata(Empty.new)
+          mapper.map(res.metadata, to: Hash)
+        end
+
+        # @return [Hash] metadata (from metadata_url)
         def metadata
           res = client.metadata(Empty.new)
-          res.metadata
+          mapper.map(res.metadata, to: Hash)
         end
 
         # @return [String] metadata url