code: public void tracef(Throwable t, String format, Object... params) {
          doLogf(Level.TRACE, FQCN, format, params, t);
      }
docs: Issue a formatted log message with a level of TRACE.
  
  @param t the throwable
  @param format the format string, as per {@link String#format(String, Object...)}
  @param params the parameters