Windows 10 has poor bandwidth when using wireguard

[Jason A. Donenfeld]

Hi Feng,

Great to hear!

You wrote:
> In the LAN environment, the download speed is 40MB/s through WIFI to access the peer.
> When the wireguard starts, the speed is down to 8MB/s.
And now:
> The speed is up to 25MB/s, 2x faster than the previous version.

So new speed is 3.125x old speed.

I'll keep thinking about the problem space and try to get us up to the
full 40MB/s.

Jason