Use {} instead of () for object construction.

Sometimes it is difficult to distinguish between
a function call and object construction. It is better
to use {} for object construction for this reason.

Author: MarekKnapek

echo_server.cpp

@@ -54,7 +54,7 @@ void handle_request(const std::error_code& error, tcp::socket socket) {
 int main()
 {
     size_t seconds = 5;
-    asio::steady_timer t(io, asio::chrono::seconds(seconds));
+    asio::steady_timer t{io, asio::chrono::seconds{seconds}};
     printf("Waiting for %zu seconds\n", seconds);
     t.async_wait([seconds](const std::error_code &e) {
         printf("------------------------------\n");