@type t() :: %ExStreamClient.Model.NotificationMarkUnreadEvent{
  channel: ExStreamClient.Model.ChannelResponse.t() | nil,
  channel_custom: %{optional(String.t()) => any()} | nil,
  channel_id: String.t() | nil,
  channel_member_count: integer() | nil,
  channel_message_count: integer() | nil,
  channel_type: String.t() | nil,
  cid: String.t() | nil,
  created_at: DateTime.t() | integer() | String.t(),
  custom: %{optional(String.t()) => any()},
  first_unread_message_id: String.t() | nil,
  grouped_unread_channels: %{optional(String.t()) => integer()} | nil,
  last_read_at: (DateTime.t() | integer() | String.t()) | nil,
  last_read_message_id: String.t() | nil,
  received_at: (DateTime.t() | integer() | String.t()) | nil,
  team: String.t() | nil,
  thread_id: String.t() | nil,
  total_unread_count: integer() | nil,
  type: String.t(),
  unread_channels: integer() | nil,
  unread_count: integer() | nil,
  unread_messages: integer() | nil,
  unread_thread_messages: integer() | nil,
  unread_threads: integer() | nil,
  user: ExStreamClient.Model.UserResponseCommonFields.t() | nil
}