Difference in output between client and server

# Context

* Version of iperf3:3.11

* Hardware: AMD64

* Operating system (and distribution, if any): VM Ubuntu 20.04

I'm running some UDP tests from my Ubuntu VM.

The command I use for the client is :

`iperf3 -u -c hostname -p xxxxx --get-server-output
`
And for server :

`iperf3 -s -1 -p xxxxx --rcv-timeout 2000`

What I observed was that there was a difference between the output of the client and the output of the server.

```
[ ID] Interval Transfer Bitrate Total Datagrams
[ 5] 0.00-1.00 sec 128 KBytes 1.05 Mbits/sec 90
[ 5] 1.00-2.01 sec 127 KBytes 1.04 Mbits/sec 89
[ 5] 2.01-3.00 sec 130 KBytes 1.07 Mbits/sec 91
[ 5] 3.00-4.00 sec 127 KBytes 1.04 Mbits/sec 89
[ 5] 4.00-5.00 sec 128 KBytes 1.05 Mbits/sec 90
[ 5] 5.00-6.00 sec 128 KBytes 1.05 Mbits/sec 90
[ 5] 6.00-7.00 sec 128 KBytes 1.05 Mbits/sec 90
[ 5] 7.00-8.00 sec 127 KBytes 1.04 Mbits/sec 89
[ 5] 8.00-9.00 sec 128 KBytes 1.06 Mbits/sec 90
[ 5] 9.00-10.00 sec 128 KBytes 1.05 Mbits/sec 90
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Jitter Lost/Total Datagrams
[ 5] 0.00-10.00 sec 1.25 MBytes 1.05 Mbits/sec 0.000 ms 0/898 (0%) sender
[ 5] 0.00-10.05 sec 1.25 MBytes 1.04 Mbits/sec 1.939 ms 0/898 (0%) receiver

Server output:

[ ID] Interval Transfer Bitrate Jitter Lost/Total Datagrams
[ 5] 0.00-1.00 sec 121 KBytes 993 Kbits/sec 1.005 ms 0/85 (0%)
[ 5] 1.00-2.00 sec 128 KBytes 1.05 Mbits/sec 1.319 ms 0/90 (0%)
[ 5] 2.00-3.00 sec 128 KBytes 1.05 Mbits/sec 1.324 ms 0/90 (0%)
[ 5] 3.00-4.00 sec 124 KBytes 1.02 Mbits/sec 1.713 ms 0/87 (0%)
[ 5] 4.00-5.00 sec 131 KBytes 1.07 Mbits/sec 1.108 ms 0/92 (0%)
[ 5] 5.00-6.00 sec 128 KBytes 1.05 Mbits/sec 2.422 ms 0/90 (0%)
[ 5] 6.00-7.00 sec 128 KBytes 1.05 Mbits/sec 0.964 ms 0/90 (0%)
[ 5] 7.00-8.00 sec 127 KBytes 1.04 Mbits/sec 2.359 ms 0/89 (0%)
[ 5] 8.00-9.00 sec 127 KBytes 1.04 Mbits/sec 1.893 ms 0/89 (0%)
[ 5] 9.00-10.00 sec 130 KBytes 1.06 Mbits/sec 1.799 ms 0/91 (0%)
[ 5] 10.00-10.05 sec 7.13 KBytes 1.15 Mbits/sec 1.939 ms 0/5 (0%)
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Jitter Lost/Total Datagrams
[ 5] 0.00-10.05 sec 1.25 MBytes 1.04 Mbits/sec 1.939 ms 0/898 (0%) receiver
```

So at the above example there is an extra interval compared with the ones of the client :

`[ 5] 10.00-10.05 sec 7.13 KBytes 1.15 Mbits/sec 1.939 ms 0/5 (0%) `

Does anybody knows why this is happening and if there is a way to always achieve the same intervals both on the client and the server side.

Thank you fro your time.