// by getMessageByCode
        errorCodeMessagesTmp.put(0, "NT_STATUS_SUCCESS");

        errorCodeMessages = Collections.unmodifiableMap(errorCodeMessagesTmp);
        dosErrorCodeStatuses = Collections.unmodifiableMap(dosErrorCodeStatusesTmp);

        final Map<Integer, String> winErrorCodeMessagesTmp = new HashMap<>();
        for (int i = 0; i < WINERR_CODES.length; i++) {

            final Map.Entry entry = (Map.Entry) entries.next();
            entry.setValue(Collections.unmodifiableList((List) entry.getValue()));
        }
        return headerFields = Collections.unmodifiableMap(map);
    }

    @Override
    public Map getHeaderFields() {
        if (headerFields != null) {
            return headerFields;
        }
        try {
            handshake();

        }
        for (final Entry<String, List<String>> entry : map.entrySet()) {
            entry.setValue(Collections.unmodifiableList(entry.getValue()));
        }
        return this.headerFields = Collections.unmodifiableMap(map);
    }

    @Override
    public Map<String, List<String>> getHeaderFields() {
        if (this.headerFields != null) {
            return this.headerFields;
        }
        handshake();

        return errorCode.getCategory();
    }

    public RetryPolicy getRetryPolicy() {
        return retryPolicy;
    }

    public Map<String, Object> getContext() {
        return Collections.unmodifiableMap(context);
    }

    public long getOperationStartTime() {
        return operationStartTime;
    }

    public String getOperationName() {
        return operationName;
    }