# File lib/mongo/grid/file/chunk.rb, line 172
          def split(io, file_info, offset = 0)
            io = StringIO.new(io) if io.is_a?(String)
            parts = Enumerator.new { |y| y << io.read(file_info.chunk_size) until io.eof? }
            parts.map.with_index do |bytes, n|
              file_info.update_md5(bytes)
              Chunk.new(
                data: BSON::Binary.new(bytes),
                files_id: file_info.id,
                n: n + offset
              )
            end
          end