def normalize_field(field)
      default_value = if field.default?
                        { default: field.default }
                      else
                        {}
                      end
      super.merge(default_value)
    end
def normalize_field(field)
      default_value = if field.default?
                        { default: field.default }
                      else
                        {}
                      end
      super.merge(default_value)
    end
TODO: include aliases once the avro Ruby gem supports them
 Note: permitted values for defaults are not enforced here.
 That should be done at the schema level, and is not done currently
 in the Avro Ruby gem