Bind to interface with client (mac)

# Context

* Version of iperf3:
iperf 3.13 (cJSON 1.7.15)

* Hardware:
MacBook Pro Intel Late 2019 i9-9900, 64gb ram

* Operating system (and distribution, if any):
Darwin MacBook-Pro-5.home 22.2.0 Darwin Kernel Version 22.2.0: Fri Nov 11 02:08:47 PST 2022; root:xnu-8792.61.2~4/RELEASE_X86_64 x86_64

Optional features available: sendfile / zerocopy, support IPv4 don't fragment

# Bug Report

* Expected Behavior
when using two network interfaces, and explicitely binding server and client to one of them, iperf3 sends data over the network, so is limited by the speed of the underlying switch (e.g. 1GBit).

* Steps to Reproduce
given two network interfaces, one bound to 10.0.0.170 and one to 10.0.0.216
1.) start the server `iperf3 -B 10.0.0.216 -s`
2.) start the client `iperf3 -B 10.0.0.170 -c 10.0.0.216`

* Actual Behavior
iperf3 does not send over the network but over the local bus (thunderbolt).

```
iperf3 -B 10.0.0.170 -c 10.0.0.216
Connecting to host 10.0.0.216, port 5201
[ 5] local 10.0.0.170 port 51306 connected to 10.0.0.216 port 5201
[ ID] Interval Transfer Bitrate
[ 5] 0.00-1.00 sec 6.56 GBytes 56.3 Gbits/sec
[ 5] 1.00-2.00 sec 6.69 GBytes 57.5 Gbits/sec
[ 5] 2.00-3.00 sec 6.47 GBytes 55.6 Gbits/sec
[ 5] 3.00-4.00 sec 6.33 GBytes 54.4 Gbits/sec
[ 5] 4.00-5.00 sec 6.55 GBytes 56.3 Gbits/sec
[ 5] 5.00-6.00 sec 6.46 GBytes 55.5 Gbits/sec
[ 5] 6.00-7.00 sec 5.07 GBytes 43.5 Gbits/sec
[ 5] 7.00-8.00 sec 113 MBytes 947 Mbits/sec
[ 5] 8.00-9.00 sec 112 MBytes 943 Mbits/sec
[ 5] 9.00-10.00 sec 112 MBytes 937 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate
[ 5] 0.00-10.00 sec 44.4 GBytes 38.2 Gbits/sec sender
[ 5] 0.00-10.00 sec 44.4 GBytes 38.2 Gbits/sec receiver

iperf Done.
```