@Override
            public Set<String> load(String service) {
                return ConcurrentHashMap.newKeySet();
            }
Cache the HTTP URIs which are not formatted by the rules per service.
Level one map key is service name, the value is a map of HTTP URIs with candidates of formatted names.
If the URI is formatted by the rules, the value would be the first 10 formatted names.
If the URI is unformatted, the value would be an empty queue.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/config/group/EndpointNameGrouping.java