code: public static void d(Object source, String format, Object... args) {
      log(source, Log.DEBUG, format, args);
    }
docs: Logs a string to the console using the source object's name as the log tag at the debug level.
  If the source object is null, the default tag (see {@link LogUtils#TAG}) is used.
  
  @param source The object that generated the log event.
  @param format A format string, see {@link String#format(String, Object...)}.
  @param args String formatter arguments.