Monitor iPhone network traffic with Wireshark
Use rvictl
and Wireshark.
In order to user rvictl you have to have latest Xcode installed and launched at least once (during first run Xcode downloads some additional tools, one of them is rvictl).
When rvictl command is available in terminal check your device UUID (in Xcode > Window > Devices and Simulators)
Then execute:
rvictl -s [UUID]
Now you should have rvi0 interface available.
Just use Wireshark on that interface, it will show all packages sent and received by your iPhone.