如何检查用户的iOS设备是否支持蓝牙对等连接

What is the best way of programatically checking if the current device supports Bluetooth peer-to-peer GameKit connectivity? I am aware of how to check for Game Center support, but want to support devices on iOS 3 that have Bluetooth (I know all devices with bluetooth can be upgraded to iOS 4).What is the best way of programatically checkin