public static Builder newBuilder(
      com.google.cloud.vision.v1p3beta1.ListReferenceImagesResponse prototype) {
    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
  }
<pre>
The next_page_token returned from a previous List request, if any.
</pre>

<code>string next_page_token = 3;</code>

@return The bytes for nextPageToken.
java-vision/proto-google-cloud-vision-v1p3beta1/src/main/java/com/google/cloud/vision/v1p3beta1/ListReferenceImagesResponse.java