public Builder setResponseHeaders(Map<String, List<String>> responseHeaders) {
            Map<String, String> headers = new HashMap<>();
            for (Entry<String, List<String>> header : responseHeaders.entrySet()) {
                if (header.getValue() != null) {
                    StringJoiner joiner = new StringJoiner(",");
                    for (String value : header.getValue()) {
                        joiner.add(value);
                    }
                    headers.put(header.getKey(), joiner.toString());
                }
            }
            this.responseHeaders = headers;
            return this;
        }
Represents a web page according the CDRv3.1 schema.
ache-tools/src/main/java/achecrawler/memex/cdr/CDR31Document.java