# File lib/mongo/grid/file/info.rb, line 232
        def to_bson(buffer = BSON::ByteBuffer.new, validating_keys = BSON::Config.validating_keys?)
          if @client_md5 && !document[:md5]
            document[:md5] = @client_md5.hexdigest
          end
          document.to_bson(buffer)
        end