openrtb-core/src/main/java/com/google/openrtb/json/OpenRtbNativeJsonWriter.java
public String writeNativeResponse(NativeResponse resp) throws IOException {
    try (StringWriter writer = new StringWriter()) {
      writeNativeResponse(resp, writer);
      return writer.toString();
    }
  }
public String writeNativeResponse(NativeResponse resp) throws IOException {
    try (StringWriter writer = new StringWriter()) {
      writeNativeResponse(resp, writer);
      return writer.toString();
    }
  }
Serializes a {@link NativeResponse} to JSON, returned as a {@link String}.