perf(http_proxy): stream the response to avoid memory bloat

Author: tkan145

gateway/src/apicast/http_proxy.lua

@@ -169,7 +169,7 @@ local function forward_https_request(proxy_uri, uri, proxy_opts)
                 return sock:send("HTTP/1.1 502 Bad Gateway")
             end
         else
-            httpc:proxy_response(res)
+            httpc:proxy_response(res, DEFAULT_CHUNKSIZE)
             httpc:set_keepalive()
         end
     else