compression :: nil | :gzip | :snappy

t :: %Cafex.Protocol.Message{attributes: integer, compression: compression, key: binary, magic_byte: integer, metadata: term, offset: integer, partition: integer, timestamp: integer, timestamp_type: atom, topic: binary, value: binary}

tuple_message ::
  {topic :: String.t, partition :: integer, value :: binary} |
  {topic :: String.t, partition :: integer, value :: binary, key :: binary | nil}