@Override
    public Node toNode() {
        ObjectNode.Builder propertiesBuilder = ObjectNode.builder();
        properties.forEach(propertiesBuilder::withMember);

        ObjectNode.Builder headersBuilder = ObjectNode.builder();
        for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
            headersBuilder.withMember(entry.getKey(), ArrayNode.fromStrings(entry.getValue()));
        }

        return ObjectNode.builder()
                .withMember(URL, url)
                .withMember(PROPERTIES, propertiesBuilder.build())
                .withMember(HEADERS, headersBuilder.build())
                .build();
    }
Gets the headers to set when sending HTTP requests to the URL.

@return a map of header names to a list of values to set on those headers.
smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/language/evaluation/value/EndpointValue.java