Question about "Switched radio while sending an AirFrame"

[wli]

Hi, I am trying to switch nodes to sleep mode in network layer. I issued commands for switching to sleep mode but got this message"Switched radio while sending an AirFrame. The effects this would have on the transmission are not simulated by the BasePhyLayer". I checked console output and there was an airframe reaching phy layer before it got to switching to sleep command. I got that txOverTimer can suggest AirFrame transmission is over. So is there a method for me to determine if airframe transmission is complete so I can do switching to sleep afterwards. Thanks.