    # File lib/chef/cookbook_site_streaming_uploader.rb, line 211
          def read(how_much)
            return nil if @part_no >= @parts.size

            how_much_current_part = @parts[@part_no].size - @part_offset

            how_much_current_part = if how_much_current_part > how_much
                                      how_much
                                    else
                                      how_much_current_part
                                    end

            how_much_next_part = how_much - how_much_current_part

            current_part = @parts[@part_no].read(@part_offset, how_much_current_part)

            # recurse into the next part if the current one was not large enough
            if how_much_next_part > 0
              @part_no += 1
              @part_offset = 0
              next_part = read(how_much_next_part)
              current_part + if next_part
                               next_part
                             else
                               ''
                             end
            else
              @part_offset += how_much_current_part
              current_part
            end
          end