@type t() :: %Grpc.Reflection.V1alpha.ServerReflectionRequest{
  __unknown_fields__: [Protobuf.unknown_field()],
  host: String.t(),
  message_request:
    {:file_by_filename, String.t()}
    | {:file_containing_symbol, String.t()}
    | {:file_containing_extension,
       Grpc.Reflection.V1alpha.ExtensionRequest.t() | nil}
    | {:all_extension_numbers_of_type, String.t()}
    | {:list_services, String.t()}
    | nil
}