}
        }
        if (!found) {
            requestProperties.put(key, values);
        }
        connection.setRequestProperty(key, value);
    }

    @Override
    public void addRequestProperty(final String key, final String value) {
        if (key == null) {
            throw new NullPointerException();
        }
        List values = null;

                if (headerList != null) {
                    for (final String[] values : headerList) {
                        logger.fine(() -> ">>> " + values[0] + "=" + values[1]);
                        connection.addRequestProperty(values[0], values[1]);
                    }
                }
                if (compression != null) {
                    connection.setRequestProperty("Accept-Encoding", compression);
                }

        }
        if (!found) {
            this.requestProperties.put(key, values);
        }
        this.connection.setRequestProperty(key, value);
    }

    @Override
    public void addRequestProperty(final String key, final String value) {
        if (key == null) {
            throw new NullPointerException();
        }
        List<String> values = null;