@java.lang.Override
  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
    for (int i = 0; i < adaptiveMtFiles_.size(); i++) {
      output.writeMessage(1, adaptiveMtFiles_.get(i));
    }
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(nextPageToken_)) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 3, nextPageToken_);
    }
    getUnknownFields().writeTo(output);
  }
<pre>
Optional. A token to retrieve a page of results. Pass this value in the
ListAdaptiveMtFilesRequest.page_token field in the subsequent call to
`ListAdaptiveMtFiles` method to retrieve the next page of results.
</pre>

<code>string next_page_token = 3 [(.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/ListAdaptiveMtFilesResponse.java