ptb6: conn [::1].4518 <-> [::1].49171
before-PTB : t_state=5 t_maxseg=14336 t_maxopd=16324 t_rttupdated=41 snd_ssthresh=28672 snd_cwnd=28676
ptb6: injected ICMPv6 PTB mtu=60 quoting ::1.4518 -> ::1.49171
after-PTB  : t_state=5 t_maxseg=14336 t_maxopd=16324 t_rttupdated=41 snd_ssthresh=28672 snd_cwnd=28676
ptb6: aborting client (SO_LINGER 0) ... tcp_close next; expect panic if t_maxseg==0 and ssthresh block entered
ptb6: close returned (no panic -- diagnose above)