Force NIC not to send a tcp packet

Question about Mellanox connectX cards: how to instruct my NIC not to send a tcp packet? So when I do send(), there is a flag for the NIC whether to send the packet out. This is to keep my instruction cache hot and when I want the packet to reach its recipient, I ask the NIC to send the packet out. The goal is to send a tcp packet once a microsecond but stop the packets at the NIC and one in a million packet with a proper flag should be sent by NIC out. How to do that?

You might be able to customize or emulate your traffic via a TCP packet generator.
Or create a script with the exact functions desired.

There are no specific instructions or specific flags within our MLNX driver that are predefined with what you are trying to accomplish as simple as turn on/off.