code: function (start, end, force) {
      var bytesRead;
  
      if (end - start > config.bufferSize) {
        return reject(new Error("Range exceeds the max buffer size"));
      }
      if (force || start < currentRange.start || (start > currentRange.end)) {
        bytesRead = fs.readSync(fd, buffer, 0, config.bufferSize, start);
        currentRange.start = start;
        currentRange.end = start + bytesRead;
        debug("buffering new range: %s", JSON.stringify(currentRange));
      }
    }
docs: Synchrounously updates the cache with a new range of data if the required
  range is not within the current cache.
  @param {Number} start Start position of the required range. Cannot be null.
  @param {Number} end End position of the required range. Cannot be null.
  @param {Boolean} force Indicates whether to force the cache update.