Don't bother testing if len is nonzero, we know it is, as we're in the
"else" part of a if (!len), and testing it confuses clang into thinking
ret may be left uninitialized.
Store object in the cache. The cache use an shctx for storage.
It uses an http-response action to store the headers and a filter to
store the body. The http-response action is used in order to allow
modifications by other actions before caching.
