Document use case for `GeneratedMessage.createEmptyInstance` (#711)
Document use case for `GeneratedMessage.createEmptyInstance` (#711)


dart-lang/protobuf,dart-lang/protobuf,google/protobuf.dart,google/protobuf.dart,dart-lang/dart-protobuf,dart-lang/dart-protobuf,dart-lang/protobuf,google/protobuf.dart,dart-lang/dart-protobuf