* modified by the caller and will only be valid for as long as the
* message is valid, (which is until the query from which it derived
* is destroyed).
+ *
+ * This function will not return NULL since Notmuch ensures that every
+ * message has a unique message ID, (Notmuch will generate an ID for a
+ * message if the original file does not contain one).
*/
const char *
notmuch_message_get_message_id (notmuch_message_t *message);