@java.lang.Override
  public final boolean isInitialized() {
    byte isInitialized = memoizedIsInitialized;
    if (isInitialized == 1) return true;
    if (isInitialized == 0) return false;

    memoizedIsInitialized = 1;
    return true;
  }
<pre>
Token to retrieve the next page of results, or empty if there are no more
results in the list.
</pre>

<code>string next_page_token = 2;</code>

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