@callback child_spec(name :: atom(), opts :: Keyword.t()) :: false | map()

@callback contains?(name :: atom(), Kvasir.topic(), Kvasir.Offset.t()) ::
  :maybe | true | false

@callback freeze(name :: atom(), Kvasir.Topic.t(), event :: map()) ::
  :ok | {:error, atom()}

@callback offsets(name :: atom(), Kvasir.topic()) ::
  {:ok, Kvasir.Offset.t()} | {:error, atom()}

@callback stream(name :: atom(), Kvasir.topic()) :: {:ok, Stream.t()} | {:error, atom()}