code: public static int v(String tag, String msg, Throwable tr) {
          return v(SUBSYSTEM.MAIN, tag, msg, tr);
      }
docs: Send a VERBOSE log message with {@link SUBSYSTEM#MAIN} as default one and log the exception.
  @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.
  @param tr An exception to log.
  
  @return