add server_builder_option
diff --git a/include/grpc++/server_builder.h b/include/grpc++/server_builder.h
index 05937f1..b324deb 100644
--- a/include/grpc++/server_builder.h
+++ b/include/grpc++/server_builder.h
@@ -37,8 +37,9 @@
 #include <memory>
 #include <vector>
 
-#include <grpc/compression.h>
+#include <grpc++/impl/server_builder_option.h>
 #include <grpc++/support/config.h>
+#include <grpc/compression.h>
 
 namespace grpc {
 
@@ -98,6 +99,8 @@
     compression_options_ = options;
   }
 
+  void SetOption(std::unique_ptr<ServerBuilderOption> option);
+
   /// Tries to bind \a server to the given \a addr.
   ///
   /// It can be invoked multiple times.
@@ -140,6 +143,7 @@
 
   int max_message_size_;
   grpc_compression_options compression_options_;
+  std::vector<std::unique_ptr<ServerBuilderOption>> options_;
   std::vector<std::unique_ptr<NamedService<RpcService>>> services_;
   std::vector<std::unique_ptr<NamedService<AsynchronousService>>>
       async_services_;