fix(core): update

ts/levelcache.abstract.classes.cache.ts

@@ -0,0 +1,25 @@
+import { CacheEntry } from "./levelcache.classes.cacheentry";
+
+export abstract class AbstractCache {
+  public abstract ready: Promise<void>;
+  public abstract status: 'active' | 'inactive';
+  
+  // Blobs
+  /**
+   * store a Blob
+   */
+  public abstract storeCacheEntryByKey(keyArg: string, valueArg: CacheEntry): Promise<void>;
+
+  // Cache Entries
+  /**
+   * retrieve cache entry
+   */
+  public abstract retrieveCacheEntryByKey(keyArg: string): Promise<CacheEntry>;
+
+  public abstract checkKeyPresence(keyArg: string): Promise<boolean>;
+
+  /**
+   * cleans the cache
+   */
+  public abstract clean(): Promise<void>;
+}