private List<Entry<String, String>> getKeys(String prefix) {
        return System.getProperties().entrySet().stream()
                .map(pair -> new AbstractMap.SimpleEntry<>(String.valueOf(pair.getKey()), String.valueOf(pair.getValue())))
                .filter(pair -> StringUtils.startsWith(pair.getKey(), prefix))
                .collect(Collectors.toList());
    }
Gets all properties in the engine configuration that are prefixed
with the given prefix.
@param prefix the prefix
@return all prefixed properties
gateway/platforms/vertx3/vertx3/src/main/java/io/apiman/gateway/platforms/vertx3/common/config/VertxEngineConfig.java