code: private String getFileFromCache(String filename) {
          LRUCache.CacheEntry<String, T> cachedTemplate = cache.get(filename);
  
          if (cachedTemplate == null) {
              return null;
          }
  
          return cache.get(filename).raw;
      }
docs: Gets the content of the file from cache this is a synchronous operation since there is no blocking or I/O