Bonjour NSStreamEventHasBytesAvailable event speed (enabled WiFi and Bluetooth both)

Question

I'm develpoing a network app using Bonjour service on iPhone devices.

My problem is that NSStreamEventHasBytesAvailable event speed is slow when i enable WiFi and Bluetooth both on my devices.

But strangely if i enable only one either WiFi or Bluetooth, NSStreamEventHasBytesAvailable event speed is fast normally.

Is it originally slow if enabled WiFi and Bluetooth both?

I have to consider this situations becuase any users can enable WiFi and Bluetooth both.

Thanks.