Checking the buffer of the access point

[Maite Furundarena]

Hello,

I'm working with ns3 for simulating IPv6 multicast traffic over WiFi networks. I need to check if the AP has any multicast packet buffered, so notify it to the nodes within the wireless network. 

Where should I check if there is any multicast packet to be sent? In the Buffer or in the Wifi-Mac-Queue? 

Thank you for your time,