private List<String> removeNormal(String normalName) {
        List<String> removed = new ArrayList<>();
        clearMatchingStartingAt(0, normalName, removed);
        return Collections.unmodifiableList(removed);
    }
Removes the header entries that match the given header name, and returns them as a list.
zuul-core/src/main/java/com/netflix/zuul/message/Headers.java