Reinject captured first packet on lazy peer activation and keep peer alive across endpoint swap

client/iface/wgproxy/bind/proxy.go

@@ -136,6 +136,15 @@ func (p *ProxyBind) CloseConn() error {
 	return p.close()
 }
 
+// InjectPacket writes b to the remote peer over the underlying transport.
+func (p *ProxyBind) InjectPacket(b []byte) error {
+	if p.remoteConn == nil {
+		return fmt.Errorf("proxy not started")
+	}
+	_, err := p.remoteConn.Write(b)
+	return err
+}
+
 func (p *ProxyBind) close() error {
 	if p.remoteConn == nil {
 		return nil