How to use the node-opcua-chunkmanager.verify_message_chunk function in node-opcua-chunkmanager

private _send_chunk(requestId: number, chunk: Buffer | null) {

        const requestData = this._requests[requestId];

        if (chunk) {

            /**
             * notify the observer that a message chunk is about to be sent to the server
             * @event send_chunk
             * @param message_chunk {Object}  the message chunk
             */
            this.emit("send_chunk", chunk);

            /* istanbul ignore next */
            if (doDebug && checkChunks) {
                verify_message_chunk(chunk);
                debugLog(chalk.yellow("CLIENT SEND chunk "));
                debugLog(chalk.yellow(messageHeaderToString(chunk)));
                debugLog(chalk.red(hexDump(chunk)));
            }
            assert(this._transport);
            this._transport.write(chunk);
            requestData.chunk_count += 1;

        } else {
            // last chunk ....

            /* istanbul ignore next */
            if (doDebug && checkChunks) {
                debugLog(chalk.yellow("CLIENT SEND done."));
            }
            if (requestData) {

const self = this;
    const request_data = self._request_data[requestId];

    if (messageChunk) {

        /**
         * notify the observer that a message chunk is about to be sent to the server
         * @event send_chunk
         * @param message_chunk {Object}  the message chunk
         */
        self.emit("send_chunk", messageChunk);

        /* istanbul ignore next */
        if (doDebug && false) {
            verify_message_chunk(messageChunk);
            debugLog("CLIENT SEND chunk ".yellow);
            debugLog(messageHeaderToString(messageChunk).yellow);
            debugLog(hexDump(messageChunk).red);
        }
        assert(self._transport);
        self._transport.write(messageChunk);
        request_data.chunk_count += 1;

    } else {
        // last chunk ....

        /* istanbul ignore next */
        if (doDebug) {
            debugLog("CLIENT SEND done.".yellow.bold);
        }
        if (request_data) {

maxChunkCount:     self.maxChunkCount
    });

    //xx acknowledgeMessage.receiveBufferSize = 8192;
    //xx acknowledgeMessage.sendBufferSize    = 8192;
    //xx console.log("xxx receiveBufferSize = ",acknowledgeMessage.receiveBufferSize , helloMessage.receiveBufferSize) ;
    //xx console.log("xxx sendBufferSize    = ",acknowledgeMessage.sendBufferSize    , helloMessage.sendBufferSize);
    //xx console.log("xxx maxMessageSize    = ",acknowledgeMessage.maxMessageSize    , helloMessage.maxMessageSize);
    //xx console.log("xxx maxChunkCount     = ",acknowledgeMessage.maxChunkCount     , helloMessage.maxChunkCount);


    const messageChunk = packTcpMessage("ACK", acknowledgeMessage);

    /* istanbul ignore next*/
    if (doDebug) {
        verify_message_chunk(messageChunk);
        debugLog("server send: " + "ACK".yellow);
        debugLog("server send: " + hexDump(messageChunk));
        debugLog("acknowledgeMessage=", acknowledgeMessage);
    }

    // send the ACK reply
    self.write(messageChunk);

};

this.sendBufferSize = clamp_value(helloMessage.sendBufferSize, 8192, 512 * 1024);
        this.maxMessageSize = clamp_value(helloMessage.maxMessageSize, 100000, 16 * 1024 * 1024);
        this.maxChunkCount = clamp_value(helloMessage.maxChunkCount, 0, 65535);

        const acknowledgeMessage = new AcknowledgeMessage({
            maxChunkCount: this.maxChunkCount,
            maxMessageSize: this.maxMessageSize,
            protocolVersion: this.protocolVersion,
            receiveBufferSize: this.receiveBufferSize,
            sendBufferSize: this.sendBufferSize
        });
        const messageChunk = packTcpMessage("ACK", acknowledgeMessage);

        /* istanbul ignore next*/
        if (doDebug) {
            verify_message_chunk(messageChunk);
            debugLog("server send: " + chalk.yellow("ACK"));
            debugLog("server send: " + hexDump(messageChunk));
            debugLog("acknowledgeMessage=", acknowledgeMessage);
        }

        // send the ACK reply
        this.write(messageChunk);

    }