Reduce the smux KeepAliveTimeout on the server from 10 to 4 minutes.

To save memory, we want to more aggressively close stale connections.

tpo/anti-censorship/pluggable-transports/snowflake#40175

server/lib/snowflake.go

@@ -217,7 +217,7 @@ func (l *SnowflakeListener) acceptStreams(conn *kcp.UDPSession) error {
 
 	smuxConfig := smux.DefaultConfig()
 	smuxConfig.Version = 2
-	smuxConfig.KeepAliveTimeout = 10 * time.Minute
+	smuxConfig.KeepAliveTimeout = 4 * time.Minute
 	smuxConfig.MaxStreamBuffer = StreamSize
 	sess, err := smux.Server(conn, smuxConfig)
 	if err != nil {