diff --git a/src/asio_client_session_impl.cc b/src/asio_client_session_impl.cc
index 5729daf5..067616e7 100644
--- a/src/asio_client_session_impl.cc
+++ b/src/asio_client_session_impl.cc
@@ -45,9 +45,9 @@ session_impl::session_impl(
       io_service_(io_service),
       resolver_(io_service),
       deadline_(io_service),
-      ping_(io_service),
       connect_timeout_(connect_timeout),
       read_timeout_(boost::posix_time::seconds(60)),
+      ping_(io_service),
       session_(nullptr),
       data_pending_(nullptr),
       data_pendinglen_(0),