cache separately for ervery client when OS return set cookie ?

[Esmq]

hi,all


i use ts(v3.2.4) for reverse proxy, and set  cache_responses_to_cookies to 4 in 
records.config,  which give the following means:
   #   4 - cache for all but text content-types except OS response
   #       without "Set-Cookie" or with "Cache-Control: public"


now i have set up a testing  original server that will returning the  
Set-Cookie header,


and i found that ts will cache separately for ervery client when OS return set 
cookie...


Client A -> TS -> OS (TS cache the response to obj1)
Client B -> TS -> OS (TS cache the response to boj2)


why A and B not use the same cached obj?