IPv6 detection，5w num， send probes so less，why？

[Abintong]

--interface ens33 --probing_rate 5000 --output 5wtest.flash --targets 5w.txt --remove_reserved_addresses=false
I0702 10:53:53.798367 241632 main.cc:257] Seed for random number generator is 0, we random generate the seed: 1719888833
I0702 10:53:53.798688 241632 blacklist.cc:40] Blacklist disabled.
I0702 10:53:53.861064 241632 traceroute.cc:243] Start preprobing.
I0702 10:53:56.861601 241632 traceroute.cc:258] Preprobing finished (Took 3 seconds).
I0702 10:53:56.861884 241632 traceroute.cc:311] Start main probing.
I0702 10:54:14.881989 241632 traceroute.cc:368] Scan finished.
I0702 10:54:14.882509 241632 traceroute.cc:375] Main probing finished (Took 18 seconds).
I0702 10:54:15.882810 241632 traceroute.cc:483] Average Sending Rate: 0.02 Kpps
I0702 10:54:15.882894 241632 traceroute.cc:485] Average Receving Rate: 0.00 Kpps
I0702 10:54:15.882905 241632 traceroute.cc:487] Sent packets: 522
I0702 10:54:15.882915 241632 traceroute.cc:489] Received packets: 0
I0702 10:54:15.882931 241632 traceroute.cc:491] Total Dropped responses: 0
I0702 10:54:15.882948 241632 traceroute.cc:494] Other dropped: 0
I0702 10:54:15.882965 241632 traceroute.cc:495] Checksum Mismatches: 0
I0702 10:54:15.882982 241632 traceroute.cc:497] Distance Abnormalities: 0
I0702 10:54:15.882999 241632 traceroute.cc:499] Sent probes: 493
I0702 10:54:15.883009 241632 traceroute.cc:500] Sent preprobes: 29
I0702 10:54:15.883025 241632 traceroute.cc:501] Hit nonstop: 0
I0702 10:54:15.883042 241632 traceroute.cc:503] Interfaces Forward-probing: 0
I0702 10:54:15.883059 241632 traceroute.cc:505] Interfaces Backward-probing: 0
I0702 10:54:15.883076 241632 traceroute.cc:509] Discovered Interfaces: 0
I0702 10:54:18.864709 241632 blacklist.cc:21] Free the blacklist.
I0702 10:54:18.864939 241632 main.cc:370] The program ends.