public static HeaderName get(String name) {
        return HEADER_NAME_CACHE.get(name);
    }
Looks up the name in the cache, and if does not exist, then creates and adds a new one
(up to the max cache size).

@param name
@return HeaderName - never null.
zuul-core/src/main/java/com/netflix/zuul/message/http/HttpHeaderNames.java