Two nodes are able to establish a WireGuard connection, as I can see the logs indicating successful handshake. The keepalive packets are also functioning properly. However, when I try to send a file from Node A to Node B, for example using the scpcommand, I noticed that the data goes through DERP first. When I check the output of tailscale status

, I see records of relays. But based on my understanding, since the WireGuard connection is already established, why does the data still have to go through DERP for transmission?