why fastopen failed from client perspective

Fields

TFO_STATUS_UNSPEC,

catch-all

TFO_COOKIE_UNAVAILABLE,

if not in TFO_CLIENT_NO_COOKIE mode

TFO_DATA_NOT_ACKED,

SYN-ACK did not ack SYN data

TFO_SYN_RETRANSMITTED,

SYN-ACK did not ack SYN data after timeout