This PR updates the Wireguard dependency and updates to use new
vectorised reads/writes, which should reduce the number of syscalls and
improve performance.
This will only make a difference on Linux as this is the only platform
for which the Wireguard TUN library supports vectorised reads/writes.
For other platforms, single reads and writes will be performed as usual.
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Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>
