@Override
    public void clear() {
        this.cache.invalidateAll();
        this.cache.cleanUp();
    }
initial caffeine cache include WeakReference cache and StrongReference cache.

<p>when the weakKey is true that means using weakKeys cache, gc will collect the weak key, please refer to:
com.github.benmanes.caffeine.cache.References.WeakKeyReference</p>

<p>when the weakKey is false, use strong reference, jvm maybe throw oom-error.</p>

<pre>{@code Map<String, Object> strongMap = new WindowTinyLFUMap<>(100, 100, Boolean.FALSE);
strongMap.put(new String("abc"), 1);
strongMap.put(new String("abc"), 1);
assert strongMap.get("abc") != null;

Map<String, Object> strongMap = new WindowTinyLFUMap<>(100, 100, Boolean.TRUE);
strongMap.put(new String("abc"), 1);
strongMap.put(new String("abc"), 1);
assert strongMap.get("abc") == null;
}</pre>

@param initialCapacity initial capacity
@param maximumSize maximum size
@param weakKey weak key
shenyu-common/src/main/java/org/apache/shenyu/common/cache/WindowTinyLFUMap.java