asyncio doesn't give you such control on TCP/IP stack layers and even hides some complex tasks such as callbacks, low-level protocols, transports.
You can do it using a raw socket.
Modules that can be useful

python-nmap
scapy
I'm just picking up some async Python and trying to write a simple TCP port scanner using the Asyncio module.
I can open a full-fledged TCP connection with 3-way handshakes via asyncio.open_connection. However, I want to create an SYN-ACK half-open connection—similar to what nmap uses—using asyncio. I was rummaging through the streams API but couldn't find anything. Is there a high-level method to do this? If not, how do I do this?
Is there an easy way to do half open TCP connection via Python Asyncio?