this is awful, but also it's about 20% better

overlay/device.go

@@ -1,17 +1,16 @@
 package overlay
 
 import (
-	"io"
 	"net/netip"
 
 	"github.com/slackhq/nebula/routing"
 )
 
 type Device interface {
-	io.ReadWriteCloser
+	TunDev
 	Activate() error
 	Networks() []netip.Prefix
 	Name() string
 	RoutesFor(netip.Addr) routing.Gateways
-	NewMultiQueueReader() (io.ReadWriteCloser, error)
+	NewMultiQueueReader() (TunDev, error)
 }