The ICMP dialer required explicit keepalive:true to send QUIC PING frames,
while the regular QUIC dialer enabled keepalive by default (10s period).
Without PING frames, quic-go's 30s idle timeout silently killed connections,
causing HTTP+ICMP tunnels to hang after periods of inactivity.
Fixesgo-gost/gost#352
Also in this commit:
- Release session mutex before calling GetConn() in both ICMP and QUIC
dialers, so a dead session doesn't block all Dial() calls while
OpenStreamSync blocks
- Add 30s timeout context to OpenStreamSync to prevent indefinite blocking
if the QUIC session dies between liveness check and stream open
- Guard session cache deletion with pointer identity check to avoid
evicting a newly created session during a race
ginuerzh