incremental
diff --git a/boost-dbus/include/dbus/detail/watch_timeout.hpp b/boost-dbus/include/dbus/detail/watch_timeout.hpp
new file mode 100644
index 0000000..ef2e708
--- /dev/null
+++ b/boost-dbus/include/dbus/detail/watch_timeout.hpp
@@ -0,0 +1,151 @@
+// Copyright (c) Benjamin Kietzman (github.com/bkietz)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef DBUS_WATCH_TIMEOUT_HPP
+#define DBUS_WATCH_TIMEOUT_HPP
+
+#include <dbus/dbus.h>
+#include <boost/asio/generic/stream_protocol.hpp>
+#include <boost/asio/steady_timer.hpp>
+
+#include <chrono>
+
+namespace dbus {
+namespace detail {
+
+static void watch_toggled(DBusWatch *dbus_watch, void *data);
+struct watch_handler {
+  DBusWatchFlags flags;
+  DBusWatch *dbus_watch;
+  watch_handler(DBusWatchFlags f, DBusWatch *w) : flags(f), dbus_watch(w) {}
+  void operator()(boost::system::error_code ec, size_t) {
+    if (ec) return;
+    dbus_watch_handle(dbus_watch, flags);
+
+    boost::asio::generic::stream_protocol::socket &socket = *static_cast<boost::asio::generic::stream_protocol::socket *>(
+        dbus_watch_get_data(dbus_watch));
+
+    watch_toggled(dbus_watch, &socket.get_io_service());
+  }
+};
+static void watch_toggled(DBusWatch *dbus_watch, void *data) {
+  boost::asio::generic::stream_protocol::socket &socket =
+      *static_cast<boost::asio::generic::stream_protocol::socket *>(dbus_watch_get_data(dbus_watch));
+
+  if (dbus_watch_get_enabled(dbus_watch)) {
+    if (dbus_watch_get_flags(dbus_watch) & DBUS_WATCH_READABLE)
+      socket.async_read_some(boost::asio::null_buffers(),
+                             watch_handler(DBUS_WATCH_READABLE, dbus_watch));
+
+    if (dbus_watch_get_flags(dbus_watch) & DBUS_WATCH_WRITABLE)
+      socket.async_write_some(boost::asio::null_buffers(),
+                              watch_handler(DBUS_WATCH_WRITABLE, dbus_watch));
+
+  } else {
+    socket.cancel();
+  }
+}
+
+static dbus_bool_t add_watch(DBusWatch *dbus_watch, void *data) {
+  if (!dbus_watch_get_enabled(dbus_watch)) return TRUE;
+
+  boost::asio::io_service &io = *static_cast<boost::asio::io_service *>(data);
+
+  int fd = dbus_watch_get_unix_fd(dbus_watch);
+
+  if (fd == -1)
+    // socket based watches
+    fd = dbus_watch_get_socket(dbus_watch);
+
+  boost::asio::generic::stream_protocol::socket &socket = *new boost::asio::generic::stream_protocol::socket(io);
+
+  socket.assign(boost::asio::generic::stream_protocol(0, 0), fd);
+
+  dbus_watch_set_data(dbus_watch, &socket, NULL);
+
+  watch_toggled(dbus_watch, &io);
+  return TRUE;
+}
+
+static void remove_watch(DBusWatch *dbus_watch, void *data) {
+  delete static_cast<boost::asio::generic::stream_protocol::socket *>(
+      dbus_watch_get_data(dbus_watch));
+}
+
+struct timeout_handler {
+  DBusTimeout *dbus_timeout;
+  timeout_handler(DBusTimeout *t) : dbus_timeout(t) {}
+  void operator()(boost::system::error_code ec) {
+    if (ec) return;
+    dbus_timeout_handle(dbus_timeout);
+  }
+};
+
+static void timeout_toggled(DBusTimeout *dbus_timeout, void *data) {
+  boost::asio::steady_timer &timer =
+      *static_cast<boost::asio::steady_timer *>(dbus_timeout_get_data(dbus_timeout));
+
+  if (dbus_timeout_get_enabled(dbus_timeout)) {
+    boost::asio::steady_timer::duration interval =
+        std::chrono::milliseconds(dbus_timeout_get_interval(dbus_timeout));
+    timer.expires_from_now(interval);
+    timer.cancel();
+    timer.async_wait(timeout_handler(dbus_timeout));
+  } else {
+    timer.cancel();
+  }
+}
+
+static dbus_bool_t add_timeout(DBusTimeout *dbus_timeout, void *data) {
+  if (!dbus_timeout_get_enabled(dbus_timeout)) return TRUE;
+
+  boost::asio::io_service &io = *static_cast<boost::asio::io_service *>(data);
+
+  boost::asio::steady_timer &timer = *new boost::asio::steady_timer(io);
+
+  dbus_timeout_set_data(dbus_timeout, &timer, NULL);
+
+  timeout_toggled(dbus_timeout, &io);
+  return TRUE;
+}
+
+static void remove_timeout(DBusTimeout *dbus_timeout, void *data) {
+  delete static_cast<boost::asio::steady_timer *>(dbus_timeout_get_data(dbus_timeout));
+}
+
+struct dispatch_handler {
+  boost::asio::io_service &io;
+  DBusConnection *conn;
+  dispatch_handler(boost::asio::io_service &i, DBusConnection *c)
+      : io(i), conn(c) {}
+  void operator()() {
+    if (dbus_connection_dispatch(conn) == DBUS_DISPATCH_DATA_REMAINS)
+      io.post(dispatch_handler(io, conn));
+  }
+};
+
+static void dispatch_status(DBusConnection *conn, DBusDispatchStatus new_status,
+                            void *data) {
+  boost::asio::io_service &io = *static_cast<boost::asio::io_service *>(data);
+  if (new_status == DBUS_DISPATCH_DATA_REMAINS)
+    io.post(dispatch_handler(io, conn));
+}
+
+static void set_watch_timeout_dispatch_functions(DBusConnection *conn,
+                                                 boost::asio::io_service &io) {
+  dbus_connection_set_watch_functions(conn, &add_watch, &remove_watch,
+                                      &watch_toggled, &io, NULL);
+
+  dbus_connection_set_timeout_functions(conn, &add_timeout, &remove_timeout,
+                                        &timeout_toggled, &io, NULL);
+
+  dbus_connection_set_dispatch_status_function(conn, &dispatch_status, &io,
+                                               NULL);
+}
+
+}  // namespace detail
+}  // namespace dbus
+
+#endif  // DBUS_WATCH_TIMEOUT_HPP