xhttp xmux connection pool

[jefcolbi]

So i learnt and tested xhttp and xmux settings. I currently have this streamSettings

"streamSettings": {
        "network": "xhttp",
        "security": "tls",
        "xhttpSettings": {
          "host": "xxxxxxxxxxxxxxxxxx",
          "path": "yyyyyyyyyyy",
          "mode": "stream-up",
          "extra": {
            "xmux": {
              "maxConcurrency": 16,
              "cMaxReuseTimes": 256,
              "hMaxReusableSecs": "1800-3600"
            },
            "downloadSettings": {
              "address": "zzzzzzzzzzzzz",
              "port": 443,
              "network": "xhttp",
              "security": "tls",
              "xhttpSettings": {
                "host": "xxxxxx",
                "path": "yyyyyyyyy",
                "mode": "stream-down",
                "extra": {
                  "xmux": {
                    "maxConnections": 14,
                    "cMaxReuseTimes": 64,
                    "hMaxReusableSecs": 3600
                  }
                }
              },
              "tlsSettings": {
                "serverName": "xxxxxxxxx",
                "alpn": ["h2"],
                "allowInsecure": true
              }
            }
          }
        },
        "tlsSettings": {
          "serverName": "xxxxxxx",
          "alpn": ["h2"],
          "allowInsecure": true
        }
      }
    }

I have this setup

xray client (android library) -> nginx proxy (tls termination + h2 -> http/1.1 downgrade) -> envoy proxy -> xray server

i don't control the nginx proxy which belong to the cdn provider. the problem is that i am billed based on the amount of requests which goes through nginx proxy. That is why i want to make xhttp xmux do the less possible requests without sacrificing performance.

So currently what xray does is that in the downloading stream it opens connections up to 14 before starting reusing like it is said in the docs. But the problem is that when downstream connection is not used it closes it and re-opens another one later. what will be good is that when a downstream connection is opened is stay open even if there is no sub-connection on it so that xray must proxy a sub connection it just uses one instead of recreating a xmux client.

here are some logs

I/GoLog   ( 2572): 2026/04/30 02:12:52.250791 [Debug] [4220221881] transport/internet/splithttp: XMUX: removing xmuxClient, IsClosed() = true, OpenUsage = 0, leftUsage = 57, LeftRequests = 2147483640, UnreusableAt = 2026-04-30 03:10:25.912252574 +0000 UTC m=+3603.337901924
I/GoLog   ( 2572): 2026/04/30 02:12:52.250846 [Debug] [4220221881] transport/internet/splithttp: XMUX: creating xmuxClient because maxConnections was not hit, xmuxClients = 13

I/GoLog   ( 2572): 2026/04/30 02:17:19.786901 [Debug] [1292941082] transport/internet/splithttp: XMUX: removing xmuxClient, IsClosed() = true, OpenUsage = 0, leftUsage = 54, LeftRequests = 2147483637, UnreusableAt = 2026-04-30 03:10:23.916696882 +0000 UTC m=+3601.342346232
I/GoLog   ( 2572): 2026/04/30 02:17:19.787011 [Debug] [1292941082] transport/internet/splithttp: XMUX: creating xmuxClient because maxConnections was not hit, xmuxClients = 13

I/GoLog   ( 2572): 2026/04/30 02:21:22.558344 [Debug] [2257966651] transport/internet/splithttp: XMUX: removing xmuxClient, IsClosed() = true, OpenUsage = 0, leftUsage = 60, LeftRequests = 2147483643, UnreusableAt = 2026-04-30 03:17:12.221033291 +0000 UTC m=+4009.646683410
I/GoLog   ( 2572): 2026/04/30 02:21:22.558407 [Debug] [2257966651] transport/internet/splithttp: XMUX: creating xmuxClient because maxConnections was not hit, xmuxClients = 13

how can i achieve static xmux clients count ?