# File lib/aws/s3/object_metadata.rb, line 65
      def []= name, value
        raise "cannot change the metadata of an object version; "+
          "use S3Object#write to create a new version with different metadata" if
          @version_id
        metadata = to_h.dup
        metadata[name.to_s] = value
        object.copy_from(object.key,
                         :metadata => metadata)
        value
      end