connection not close from server side

[ChenLingPeng]

I have tested this example and find that after quit telnet, the server side will have a connection in CLOSE_WAIT. Is there a way to fix this problem?

root@ubuntu-bionic:/home/vagrant# netstat -anpt | grep CLOSE_WAIT
tcp6       0      0 10.0.2.15:12345         10.0.2.15:39022         CLOSE_WAIT  11645/sockmap
tcp6       0      0 10.0.2.15:12345         10.0.2.15:39026         CLOSE_WAIT  11645/sockmap