Enable net.inet.tcp.delayed_ack by default to improve concurrent performance.

Author: jfb8856606

config.ini

@@ -183,7 +183,7 @@ net.inet.tcp.recvbuf_inc=524288
 net.inet.tcp.sack.enable=1
 net.inet.tcp.blackhole=1
 net.inet.tcp.msl=2000
-net.inet.tcp.delayed_ack=0
+net.inet.tcp.delayed_ack=1
 
 net.inet.udp.blackhole=1
 net.inet.ip.redirect=0