set(requestId, response, size = 0) {
    if (this._cachedRequests[requestId]) {
      this.delete(requestId);
    }

    this._cachedRequests[requestId] = {
      createdAt: Date.now(),
      size,
      response,
    };

    this._size += size;
  }
Store an item in the cache
@param {string} requestId key by which the request is stored
@param {CacheResponse} response the cached response
@param {number} size the response size