examples: spawn async gio task on the current thread context

Author: pbor

examples/gio_task/file_size/ffi.rs

@@ -31,7 +31,7 @@ pub unsafe extern "C" fn my_file_size_get_file_size_async(
         closure,
     );
 
-    glib::MainContext::default().spawn_local(async move {
+    glib::MainContext::ref_thread_default().spawn_local(async move {
         let size = gio::File::for_path("Cargo.toml")
             .query_info_future("*", gio::FileQueryInfoFlags::NONE, glib::PRIORITY_DEFAULT)
             .await

examples/gio_task/file_size/mod.rs

@@ -39,7 +39,7 @@ impl FileSize {
             )
         };
 
-        glib::MainContext::default().spawn_local(async move {
+        glib::MainContext::ref_thread_default().spawn_local(async move {
             let size = gio::File::for_path("Cargo.toml")
                 .query_info_future("*", gio::FileQueryInfoFlags::NONE, glib::PRIORITY_DEFAULT)
                 .await