docs: public static final String formatTime(long timestamp, boolean useIsoDateFormat) {
          BurstDateFormat[] dfs = dateformats.get();
          if (dfs == null) {
              dfs = new BurstDateFormat[useIsoDateFormat ? 2 : 1];
              dateformats.set(dfs);
          } else if (useIsoDateFormat && dfs.length == 1) {
              BurstDateFormat[] newDfs = new BurstDateFormat[2];
              newDfs[0] = dfs[0];
              dfs = newDfs;
              dateformats.set(dfs);
          }
  
          int index = useIsoDateFormat ? 1 : 0;
          BurstDateFormat df = dfs[index];
          if (df == null) {
              df = dfs[index] = new BurstDateFormat(new SimpleDateFormat(useIsoDateFormat ? "yyyy-MM-dd'T'HH:mm:ss.SSSZ" : localeDatePattern));
          }
  
          return df.format(timestamp);
      }