final Map<String, List<String>> map = new HashMap<>();
            headers.entrySet().stream().filter(e -> e.getKey() != null)
                    .forEach(e -> map.put(e.getKey().toLowerCase(Locale.ROOT), e.getValue()));
            this.headers = map;
        }
    }

    public Map<String, List<String>> getHeaders() {
        return headers;
    }

    public String[] getHeaderValues(final String name) {