* @param key The configuration key (SR_CONF_*).
* @param data Pointer to a GVariant where the value will be stored. Must
* not be NULL. The caller is given ownership of the GVariant
* and must thus decrease the refcount after use. However if
* this function returns an error code, the field should be
* considered unused, and should not be unreferenced.
* @param key The configuration key (SR_CONF_*).
* @param data Pointer to a GVariant where the value will be stored. Must
* not be NULL. The caller is given ownership of the GVariant
* and must thus decrease the refcount after use. However if
* this function returns an error code, the field should be
* considered unused, and should not be unreferenced.