protoc_plugin/test/protos/proto3_optional.proto

// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

syntax = "proto3";

package third_party.dart.protoc_plugin.test.protos;

message Foo {
  optional int32 optional_field = 1;
  int32 non_optional_field = 2;
  optional Submessage optional_submessage = 3;
  Submessage non_optional_submessage = 4;
}

message Submessage {
 int32 a = 1;
}