I've just downloaded an app from the App Store called System Status which gives you detailed information about the iPhone it's installed on.
One of the features provides a system log which allows you to see the network info when you roam from one BSSID to another.
My question is how did they do this?
I have searched everywhere and the only way I have found requires the use of private APIs. I am assuming that since this app is live on the App Store there is a legal way to obtain the information.