@Override
    public Cancellable removeEntry(final String key, final FutureCallback<Boolean> callback) {
        Args.notEmpty(key, "Key");
        Args.notNull(callback, "Callback");
        try {
            cacheStorage.removeEntry(key);
            callback.completed(Boolean.TRUE);
        } catch (final Exception ex) {
            callback.failed(ex);
        }
        return Operations.nonCancellable();
    }
{@link HttpAsyncCacheStorage} implementation that emulates asynchronous
behavior using an instance of classic {@link HttpCacheStorage}.

@since 5.0
httpclient5-cache/src/main/java/org/apache/hc/client5/http/cache/HttpAsyncCacheStorageAdaptor.java