code: func (v *FileChooser) SetFilename(filename string) bool {
  	cstr := C.CString(filename)
  	defer C.free(unsafe.Pointer(cstr))
  	c := C.gtk_file_chooser_set_filename(v.native(), cstr)
  	return gobool(c)
  }
docs: // SetFilename is a wrapper around gtk_file_chooser_set_filename().