Method fixed

cpp/fory/meta/field_info.h:233–233

    return copy;
  }
  constexpr FieldMeta fixed() const { return with_spec(spec_.fixed()); }
  constexpr FieldMeta varint() const { return with_spec(spec_.varint()); }
  constexpr FieldMeta tagged() const { return with_spec(spec_.tagged()); }
  constexpr FieldMeta list(FieldNodeSpec elem) const {