code: private String formatLogString(Diagnostics diagnostics) {
  
      StringBuilder sb = new StringBuilder();
      sb.append(LOG_STRING_PREFIX).append(SEPARATOR);
      if (null != diagnostics.getId()) {
        sb.append("id=").append(diagnostics.getId()).append(SEPARATOR);
      }
      if (null != diagnostics.getTimestamp()) {
        sb.append("date=").append(formatter.format(new DateTime(diagnostics.getTimestamp()).toDate())).append(SEPARATOR);
      }
      if (null != diagnostics.getTag()) {
        sb.append("tag=").append(diagnostics.getTag()).append(SEPARATOR);
      }
      if (null != diagnostics.getInfo()) {
        sb.append("info=").append(diagnostics.getInfo()).append(SEPARATOR);
      }
  
      return sb.toString();
    }
docs: prefix::id=[]::date=[]::tag=[]::info=[]