How to get RX/TX bytes for a specific client?

Hi guys,

How to get RX/TX bytes for a specific client?

For an interface it was pretty easy.

:put [/interface get [find name=wlan1-BxT] tx-byte]
:put [/interface get [find name=wlan1-BxT] rx-byte]

But no idea how to get an overview about the used bandwidth for a single client of wlan1-BxT.

Thanks for helping!