code: public static CacheFrame[] get(Throwable throwable) {
      if (throwable == null) {
        return null;
      }
      Map<Throwable, CacheFrame[]> weakMap = cache.get();
      return weakMap.get(throwable);
    }
docs: Get the cached frames associated with the given throwable.
  
  @param throwable a throwable to use as a cache key.
  @return the list of frames previously cached or null.