+ * .resptr: initially NULL. Later, same as cache[x][y] pointer to a cached
+ * response, or (a rare case) a "fake cache" entry:
+ * all cache[hash(request)][0..7] blocks were found busy,
+ * the result won't be cached.
+ * .respos: "write-out to client" offset
+ * .cache_pp: initially NULL. Later, &cache[x][y] where the response is,
+ * or will be stored. Remains NULL if "fake cache" entry is in use
+ *