source: TFP-WebServer/WebServer/src/FileCache/AbstractCache.cs@ 467

using System.Collections.Generic;

namespace Webserver.FileCache {
        public abstract class AbstractCache {
                public abstract byte[] GetFileContent (string _filename);
                public abstract (int filesDropped, int bytesDropped) Invalidate ();

                protected AbstractCache () {
                        caches.Add (this);
                }

                private static readonly List<AbstractCache> caches = new List<AbstractCache> ();
                public static (int, int) InvalidateAllCaches () {
                        int filesDropped = 0;
                        int bytesDropped = 0;
                        
                        foreach (AbstractCache cache in caches) {
                                (int files, int bytes) = cache.Invalidate ();
                                filesDropped += files;
                                bytesDropped += bytes;
                        }

                        return (filesDropped, bytesDropped);
                }
        }
}