text: Title: Implement “refresh_cache” for Request.meta
  Body: At the moment, you can set `dont_cache` in `Request.meta` to have your request bypass the cache.
  
  However, what if you want the cache not to be read, but be written? For example, if you detect you got a bad HTTP 200, and you want to retry without the retry request fetching the bad response from the cache again.
  
  Workaround: implement your own middleware:
  
  ```python
  from scrapy import Spider
  from scrapy.downloadermiddlewares.httpcache import HttpCacheMiddleware as _HttpCacheMiddleware
  
  
  class HttpCacheMiddleware(_HttpCacheMiddleware):
  
      def process_request(self, request: Request, spider: Spider) -> Optional[Response]:
          if request.meta.get("refresh_cache", False):
              return None
          return super().process_request(request, spider)
  
  class MySpider(Spider):
      custom_settings = {
          'DOWNLOADER_MIDDLEWARES': {
              'scrapy.downloadermiddlewares.httpcache.HttpCacheMiddleware': None,
              HttpCacheMiddleware: 900,
          },
      }
  ```