         return this;       }        private io.confluent.kafka.serializers.protobuf.test.NestedTestProto.NestedMessage nestedMessage_;       private com.google.protobuf.SingleFieldBuilderV0<           io.confluent.kafka.serializers.protobuf.test.NestedTestProto.NestedMessage, io.confluent.kafka.serializers.protobuf.test.NestedTestProto.NestedMessage.Builder, io.confluent.kafka.serializers.protobuf.test.NestedTestProto.NestedMessageOrBuilder> 