@java.lang.Override
  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(indexEndpoint_)) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, indexEndpoint_);
    }
    if (queryCase_ == 2) {
      output.writeMessage(2, (com.google.cloud.visionai.v1.ImageQuery) query_);
    }
    if (queryCase_ == 3) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 3, query_);
    }
    for (int i = 0; i < criteria_.size(); i++) {
      output.writeMessage(4, criteria_.get(i));
    }
    if (pageSize_ != 0) {
      output.writeInt32(5, pageSize_);
    }
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(pageToken_)) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 6, pageToken_);
    }
    for (int i = 0; i < exclusionCriteria_.size(); i++) {
      output.writeMessage(7, exclusionCriteria_.get(i));
    }
    getUnknownFields().writeTo(output);
  }
<pre>
The continuation token to fetch the next page. If empty, it means it is
fetching the first page.
</pre>

<code>string page_token = 6;</code>

@return The bytes for pageToken.
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/SearchIndexEndpointRequest.java