code: public DbxDownloadStyleBuilder<R> range(long start, long length) {
          if (start < 0) throw new IllegalArgumentException("start must be non-negative");
          if (length < 1) throw new IllegalArgumentException("length must be positive");
  
          this.start = start;
          this.length = length;
  
          return this;
      }
docs: Sets the partial byte range to download.
  
  Only the specified bytes of the content will be downloaded. The HTTP Range header will be set
  for this request. If {@code start} is greater than the length of the content, the range
  request will be ignored and server will return the entire contents. If {@code length} extends
  beyond the end of the cont`ent, the server will return all bytes from {@code start} until the
  end of the content.
  
  @param start index of first byte in range (index starts at 0)
  @param length number of bytes to download starting at {@code start}
  
  @return this builder
  
  @throws IllegalArgumentException if {@code start} or {@code length} are negative