() {         if (nestedMessageBuilder_ == null) {           nestedMessageBuilder_ = new 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>