code: func (v *ComboBoxText) InsertText(position int, text string) {
  	cstr := C.CString(text)
  	defer C.free(unsafe.Pointer(cstr))
  	C.gtk_combo_box_text_insert_text(v.native(), C.gint(position), (*C.gchar)(cstr))
  }
docs: // InsertText is a wrapper around gtk_combo_box_text_insert_text().