docs: private static long deriveTokenInterval(ImmutableSortedSet<Integer> tokens)
      {
          long interval = 0;
          int count = 4;
          int prevToken = Integer.MIN_VALUE;
          UnmodifiableIterator<Integer> tokenIter = tokens.iterator();
          while (tokenIter.hasNext() && count-- > 0) {
              int nextToken = tokenIter.next();
              interval = Math.max(interval, nextToken - prevToken);
              prevToken = nextToken;
          }
          return interval;
      }