func New[T any]() *Cache[T] {
	return &Cache[T]{}
}

// NewFromFunc allocates a new cached value instance and initializes it with an
// update function, making it ready for use.
func NewFromFunc[T any](ttl time.Duration, opts Opts, update func(ctx context.Context) (T, error)) *Cache[T] {
	return &Cache[T]{
		ttl:      ttl,
		updateFn: update,
		opts:     opts,
	}
}

		return selected, true
	}

	// If cached is nil we shall skip the entry.
	if selected.cached == nil {
		return nil, false
	}

	// Merge if we have disagreement.
	// Create a new merged result.
	selected = &metaCacheEntry{
		name:     selected.name,
		reusable: true,
		cached:   &xlMetaV2{metaV: selected.cached.metaV},
	}

    assertThat(removalListener.getCount()).isEqualTo(1);

    // 2 will be cached
    assertThat(cache.getUnchecked(2)).isEqualTo(2);
    assertThat(cache.asMap().keySet()).containsExactly(2);

    CacheTesting.processPendingNotifications(cache);
    CacheTesting.checkValidState(cache);
    assertThat(removalListener.getCount()).isEqualTo(1);

    // 4 will be cached

            return null;
        }
        VersionRange cached = CACHE_VERSION.get(version);
        if (cached == null) {
            List<Restriction> restrictions = Collections.emptyList();
            cached = new VersionRange(new DefaultArtifactVersion(version), restrictions);
            CACHE_VERSION.put(version, cached);
        }
        return cached;
    }

    /**

        }

        ResolutionGroup cached = cache.get(
                artifact,
                request.isResolveManagedVersions(),
                request.getLocalRepository(),
                request.getRemoteRepositories());

        if (cached != null
                // if the POM has no file, we cached a missing artifact, only return the cached data if no update forced

    /**
     * Puts the specified data into the cache. <strong>Warning:</strong> The cache will directly save the provided
     * reference. If the cached data is mutable, i.e. could be modified after being put into the cache, the caller is
     * responsible for creating a copy of the original data and store the copy in the cache.
     *
     * @param request The repository request from which this cache was retrieved, must not be {@code null}.

    for (LoadingCache<Object, Object> cache : caches()) {
      // don't let the entries get GCed
      List<Entry<Object, Object>> unused = warmUp(cache);
      assertEquals(WARMUP_SIZE, cache.size());
      assertMapSize(cache.asMap(), WARMUP_SIZE);
      checkValidState(cache);
    }
  }

  public void testContainsKey_found() {
    for (LoadingCache<Object, Object> cache : caches()) {
      // don't let the entries get GCed

    for (LoadingCache<Object, Object> cache : caches()) {
      // don't let the entries get GCed
      List<Entry<Object, Object>> unused = warmUp(cache);
      assertEquals(WARMUP_SIZE, cache.size());
      assertMapSize(cache.asMap(), WARMUP_SIZE);
      checkValidState(cache);
    }
  }

  public void testContainsKey_found() {
    for (LoadingCache<Object, Object> cache : caches()) {
      // don't let the entries get GCed

		case "Deleted":
			z.Deleted, bts, err = msgp.ReadBoolBytes(bts)
			if err != nil {
				err = msgp.WrapError(err, "Deleted")
				return
			}
		case "Cached":
			z.Cached, bts, err = msgp.ReadBoolBytes(bts)
			if err != nil {
				err = msgp.WrapError(err, "Cached")
				return
			}
		case "NoMetadata":
			z.NoMetadata, bts, err = msgp.ReadBoolBytes(bts)
			if err != nil {
				err = msgp.WrapError(err, "NoMetadata")

	t := time.Now().Unix()
	e.init.Do(func() {
		e.cached.Store(&AccElem{})
		atomic.StoreInt64(&e.cachedSec, t)
	})
	acc := e.cached.Load()
	if lastT := atomic.LoadInt64(&e.cachedSec); lastT != t {
		// Check if lastT was changed by someone else.
		if atomic.CompareAndSwapInt64(&e.cachedSec, lastT, t) {
			// Now we swap in a new.
			newAcc := &AccElem{}
			old := e.cached.Swap(newAcc)
			var a AccElem