In "psock_send_eventhandler",when retransmit count bigger TCP_MAXRTX nuttx will set release wrb. But before this it will also set "conn->tx_unacked = 0" if we only retransmit one packet(conn->tx_unacked == sent),and In func "tcp_timer" only "conn->tx_unacked > 0" will close the tcp conn. So app will never close if nuttx retransmit over max timers.
Signed-off-by: meijian <meijian@xiaomi.com>