miss(item, entry) {
    return new BasicCache(
      this.cache.update(item, existingEntry => {
        if (existingEntry && existingEntry.dispatchId > entry.dispatchId) {
          throw new Error('Refusing to cache older value')
        }
        return entry
      })
    )
  }
Updates this cache when it is determined to **not** contain the associated value
@param {Object} item
@param {CacheEntry} entry
@return {BasicCache}