Write formatted data to a string and send the string to a user callback.
@param cinfo Codec context info
@param event_type Event type or callback to use to send the message
-@param fmt Format-control string (plus optionnal arguments)
+@param fmt Format-control string (plus optional arguments)
@return Returns true if successful, returns false otherwise
*/
opj_bool opj_event_msg(opj_common_ptr cinfo, int event_type, const char *fmt,