code: public static int d(String msg) {
          // This is a quick check to avoid the expensive stack trace reflection.
          if (!activated) {
              return 0;
          }
  
          String caller = LogHelper.getCaller();
          if (caller != null) {
              return d(caller, msg);
          }
          return 0;
      }
docs: Send a {@link #Constants.DEBUG} log message.
  
  @param msg
  The message you would like logged.