@Override
    public int getSerializedSize() {
      int size = memoizedSize;
      if (size != -1) return size;

      size = 0;
      if (((bitField0_ & 0x00000001) != 0)) {
        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
      }
      if (((bitField0_ & 0x00000002) != 0)) {
        size += com.google.protobuf.CodedOutputStream
          .computeInt32Size(2, id_);
      }
      if (((bitField0_ & 0x00000004) != 0)) {
        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(3, email_);
      }
      size += getUnknownFields().getSerializedSize();
      memoizedSize = size;
      return size;
    }
<code>optional string email = 3;</code>
@return The bytes for email.
core/src/test/java/com/alibaba/fastjson2/protobuf/PersonOuterClass.java