@type t() ::
  %ArchAstro.Types.ChannelPayloads.ApiChatChannel.ApiChatPostSimpleMessage.Response.Nested.MessageAttachmentsItemVariantsItem{
    content_type: String.t() | ArchAstro.Unset.t(),
    created_at: DateTime.t() | ArchAstro.Unset.t(),
    file: String.t() | ArchAstro.Unset.t(),
    filename: String.t() | ArchAstro.Unset.t(),
    height: integer() | ArchAstro.Unset.t(),
    id: String.t(),
    image_source:
      ArchAstro.Types.ChannelPayloads.ApiChatChannel.ApiChatPostSimpleMessage.Response.Nested.MessageAttachmentsItemVariantsItemImageSource.t()
      | ArchAstro.Unset.t(),
    updated_at: DateTime.t() | ArchAstro.Unset.t(),
    url: String.t() | ArchAstro.Unset.t(),
    variant_key: String.t() | ArchAstro.Unset.t(),
    width: integer() | ArchAstro.Unset.t()
  }