@Override
        protected boolean removeEldestEntry(Entry<String, CacheEntry> eldest) {
            final boolean remove = super.removeEldestEntry(eldest);
            if (remove) {
                logger.debug("Evicted: '{}' does not support {}", eldest.getKey(), eldest.getValue());
            }

            return remove;
        }
Keeps the recent {@link SessionProtocol} negotiation failures. It is an LRU cache which keeps at most
64k 'host name + port' pairs.
core/src/main/java/com/linecorp/armeria/client/SessionProtocolNegotiationCache.java