public String getHeaderField(String header) {
        try {
            handshake();
        } catch (IOException ex) { }
        return connection.getHeaderField(header);
    }

    private Map getHeaderFields0() {
        if (headerFields != null) return headerFields;
        Map map = new HashMap();
        String key = connection.getHeaderFieldKey(0);
        String value = connection.getHeaderField(0);

    @Override
    public String getHeaderField ( String header ) {
        handshake();
        return this.connection.getHeaderField(header);
    }


    private Map<String, List<String>> getHeaderFields0 () {
        if ( this.headerFields != null )
            return this.headerFields;
        Map<String, List<String>> map = new HashMap<>();
        String key = this.connection.getHeaderFieldKey(0);