protobufってoptionalを付けまくった方がいいっぽい?

[yosupo06]

https://protobuf.dev/programming-guides/proto3/

If no explicit field label is applied, the default field label, called “implicit field presence,” is assumed. (You cannot explicitly set a field to this state.) A well-formed message can have zero or one of this field (but not more than one). You also cannot determine whether a field of this type was parsed from the wire. An implicit presence field will be serialized to the wire unless it is the default value. For more on this subject, see [Field Presence](https://protobuf.dev/programming-guides/field_presence).

とはいったい

[yosupo06]

これserializedされたバイト列の話か　うっかり