public final Builder mergeUnknownFields(
                                                final com.google.protobuf.UnknownFieldSet unknownFields) {
            return this;
        }
<code>.com.alipay.sofa.rpc.protobuf.Group group = 2;</code>
example/src/test/java/com/alipay/sofa/rpc/protobuf/EchoRequest.java