[ns] Introducing delay before routing packet delivery

[Syed Md. Ashraful Karim]

Hi
I want to add some delay before forwarding some types routing
packet in ns-2, i.e. in the Agent's send_packet() function which
eventually call the Scheduler for a packet dispatch. 
e.g. A node should delay say for 50 microsecond before the packet delivery.
I want to add delay in C++ code to my extended Agent, or if there is any easy solution that is welcome too.

I should mention, it is not like using DelayBox.

I tried with usleep(), but it seems its not working.
Can anyone tell me a little bit more or any sample code? 
Thanks in advance. 

regards,
ashraf