public void AddStaticMetadata(string key, string value)
{
IntPtr native_key = GLib.Marshaller.StringToPtrGStrdup (key);
IntPtr native_value = GLib.Marshaller.StringToPtrGStrdup (value);
gst_element_class_add_static_metadata(LookupGType().GetClassPtr (), native_key, native_value);
GLib.Marshaller.Free (native_key);
GLib.Marshaller.Free (native_value);
}