code: public void setRange(long start, long end) {
          checkArgument(start >= 0, "start should be non-negative.");
          checkArgument(start <= end, "start should not be greater than end");
          this.range = new long[]{start, end};
      }
docs: Sets the optional inclusive byte range within the desired object that will be downloaded by this request.
  <p>
  The first byte in an object has  position 0; as an example, the first ten bytes of an object can be
  downloaded by specifying a range of 0 to 9.
  <p>
  If no byte range is specified, this request downloads the entire object from Baidu Bos.
  
  @param start The start of the inclusive byte range to download.
  @param end The end of the inclusive byte range to download.