Function gio_sys::g_dbus_proxy_call_sync

pub unsafe extern "C" fn g_dbus_proxy_call_sync(
    proxy: *mut GDBusProxy, 
    method_name: *const c_char, 
    parameters: *mut GVariant, 
    flags: GDBusCallFlags, 
    timeout_msec: c_int, 
    cancellable: *mut GCancellable, 
    error: *mut *mut GError
) -> *mut GVariant