Add mappers for synced folder client -> vagrant synced folder

plugins/commands/serve/mappers.rb

@@ -22,6 +22,7 @@ module VagrantPlugins
         Client::Project => Vagrant::Environment,
         Client::Target => Vagrant::Machine,
         Client::Terminal => Vagrant::UI::Remote,
+        Client::SyncedFolder => Vagrant::Plugin::V2::SyncedFolder,
       }
 
       include Util::HasLogger

plugins/commands/serve/mappers/synced_folder.rb

@@ -30,7 +30,7 @@ module VagrantPlugins
       end
 
       # Build a synced folder client from a proto instance
-      class SyncedFolderFromProto < Mapper
+      class SyncedFolderClientFromProto < Mapper
         def initialize
           inputs = [].tap do |i|
             i << Input.new(type: SDK::Args::SyncedFolder)
@@ -64,6 +64,20 @@ module VagrantPlugins
           Client::SyncedFolder.load(proto, broker: broker)
         end
       end
+
+      # Build a synced folder from a synced folder client
+      class SyncedFolderFromProto < Mapper
+        def initialize
+          inputs = [].tap do |i|
+            i << Input.new(type: Client::SyncedFolder)
+          end
+          super(inputs: inputs, output: Vagrant::Plugin::V2::SyncedFolder, func: method(:converter))
+        end
+
+        def converter(client)
+          Vagrant::Plugin::V2::SyncedFolder.new(client)
+        end
+      end
     end
   end
 end