I initially made this change when hacking wgengine to also capture wireguard packets going into the magicsock, so that we could capture the initial wireguard handshake.
I don't think we should ship that additional capture logic, but... it seems generally useful to capture packets from the get go on speedtest, so that you can see disco and pings before the TCP speedtest session starts.
When an agent receives a node, it responds with an ACK which is relayed
to the client. After the client receives the ACK, it's allowed to begin
pinging.
Currently, importing `codersdk` just to interact with the API requires
importing tailscale, which causes builds to fail unless manually using
our fork.