@Override
    public void writeTo(com.google.protobuf.CodedOutputStream output)
                        throws java.io.IOException {
      if (level_ != LEVEL.C1.getNumber()) {
        output.writeEnum(1, level_);
      }
      if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(id_)) {
        com.google.protobuf.GeneratedMessageV3.writeString(output, 2, id_);
      }
      if (years_ != 0) {
        output.writeInt32(3, years_);
      }
      getUnknownFields().writeTo(output);
    }
<code>int32 years = 3;</code>
@return The years.
core/src/test/java/com/alibaba/fastjson2/dubbo/GoogleProtobufBasic.java