* @G_PARAM_WRITABLE: the parameter is writable
* @G_PARAM_READWRITE: alias for %G_PARAM_READABLE | %G_PARAM_WRITABLE
* @G_PARAM_CONSTRUCT: the parameter will be set upon object construction
* @G_PARAM_WRITABLE: the parameter is writable
* @G_PARAM_READWRITE: alias for %G_PARAM_READABLE | %G_PARAM_WRITABLE
* @G_PARAM_CONSTRUCT: the parameter will be set upon object construction