group :: %{error: Cafex.Protocol.error, group_id: binary, state: binary, protocol_type: binary, protocol: binary, members: [member]}

member :: %{member_id: binary, client_id: binary, client_host: binary, member_metadata: Cafex.Protocol.JoinGroup.Request.protocol_metadata, member_assignment: Cafex.Protocol.SyncGroup.Request.member_assignment}

t :: %Cafex.Protocol.DescribeGroups.Response{groups: [group]}