public static Builder newBuilder(
      com.google.cloud.translate.v3.ListAdaptiveMtSentencesResponse prototype) {
    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
  }
<pre>
Optional.
</pre>

<code>string next_page_token = 2 [(.google.api.field_behavior) = OPTIONAL];</code>

@return The bytes for nextPageToken.
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/ListAdaptiveMtSentencesResponse.java