public static int d(String tag, String msg) {
        return d(SUBSYSTEM.MAIN, tag, msg);
    }
public static int d ( String tag , String msg ) { return d ( SUBSYSTEM . MAIN , tag , msg ) ; }
Send a DEBUG log message with {@link SUBSYSTEM#MAIN} as default one
@param tag Used to identify the source of a log message. It usually identifies the class or
activity where the log call occurs.
@param msg The message you would like logged.
@return