diff --git a/src/core/debug.go b/src/core/debug.go
index 0fc08259..eb406798 100644
--- a/src/core/debug.go
+++ b/src/core/debug.go
@@ -1,3 +1,4 @@
+//go:build debug
 // +build debug
 
 package core
diff --git a/src/core/tcp_darwin.go b/src/core/tcp_darwin.go
index 6b85c621..2ea3abc8 100644
--- a/src/core/tcp_darwin.go
+++ b/src/core/tcp_darwin.go
@@ -1,3 +1,4 @@
+//go:build darwin
 // +build darwin
 
 package core
diff --git a/src/core/tcp_linux.go b/src/core/tcp_linux.go
index 558b4e56..e59c3121 100644
--- a/src/core/tcp_linux.go
+++ b/src/core/tcp_linux.go
@@ -1,3 +1,4 @@
+//go:build linux
 // +build linux
 
 package core
diff --git a/src/core/tcp_other.go b/src/core/tcp_other.go
index 97b81ed1..8dd76f28 100644
--- a/src/core/tcp_other.go
+++ b/src/core/tcp_other.go
@@ -1,3 +1,4 @@
+//go:build !darwin && !linux
 // +build !darwin,!linux
 
 package core
diff --git a/src/defaults/defaults_darwin.go b/src/defaults/defaults_darwin.go
index e16f398f..060ce814 100644
--- a/src/defaults/defaults_darwin.go
+++ b/src/defaults/defaults_darwin.go
@@ -1,3 +1,4 @@
+//go:build darwin
 // +build darwin
 
 package defaults
diff --git a/src/defaults/defaults_freebsd.go b/src/defaults/defaults_freebsd.go
index 6c3e1c60..84df48ad 100644
--- a/src/defaults/defaults_freebsd.go
+++ b/src/defaults/defaults_freebsd.go
@@ -1,3 +1,4 @@
+//go:build freebsd
 // +build freebsd
 
 package defaults
diff --git a/src/defaults/defaults_linux.go b/src/defaults/defaults_linux.go
index 95c7ae95..c7f5f119 100644
--- a/src/defaults/defaults_linux.go
+++ b/src/defaults/defaults_linux.go
@@ -1,3 +1,4 @@
+//go:build linux
 // +build linux
 
 package defaults
diff --git a/src/defaults/defaults_openbsd.go b/src/defaults/defaults_openbsd.go
index ef339546..0ec877ca 100644
--- a/src/defaults/defaults_openbsd.go
+++ b/src/defaults/defaults_openbsd.go
@@ -1,3 +1,4 @@
+//go:build openbsd
 // +build openbsd
 
 package defaults
diff --git a/src/defaults/defaults_other.go b/src/defaults/defaults_other.go
index d1417322..37637425 100644
--- a/src/defaults/defaults_other.go
+++ b/src/defaults/defaults_other.go
@@ -1,3 +1,4 @@
+//go:build !linux && !darwin && !windows && !openbsd && !freebsd
 // +build !linux,!darwin,!windows,!openbsd,!freebsd
 
 package defaults
diff --git a/src/defaults/defaults_windows.go b/src/defaults/defaults_windows.go
index e81d09cf..c1ea9689 100644
--- a/src/defaults/defaults_windows.go
+++ b/src/defaults/defaults_windows.go
@@ -1,3 +1,4 @@
+//go:build windows
 // +build windows
 
 package defaults
diff --git a/src/ipv6rwc/ipv6rwc.go b/src/ipv6rwc/ipv6rwc.go
index 1c715f0f..fc2a688f 100644
--- a/src/ipv6rwc/ipv6rwc.go
+++ b/src/ipv6rwc/ipv6rwc.go
@@ -132,6 +132,7 @@ func (k *keyStore) update(key ed25519.PublicKey) *keyInfo {
 	var kArray keyArray
 	copy(kArray[:], key)
 	var info *keyInfo
+	var packets [][]byte
 	if info = k.keyToInfo[kArray]; info == nil {
 		info = new(keyInfo)
 		info.key = kArray
@@ -140,19 +141,19 @@ func (k *keyStore) update(key ed25519.PublicKey) *keyInfo {
 		k.keyToInfo[info.key] = info
 		k.addrToInfo[info.address] = info
 		k.subnetToInfo[info.subnet] = info
-		k.resetTimeout(info)
-		k.mutex.Unlock()
 		if buf := k.addrBuffer[info.address]; buf != nil {
-			k.core.WriteTo(buf.packet, iwt.Addr(info.key[:]))
+			packets = append(packets, buf.packet)
 			delete(k.addrBuffer, info.address)
 		}
 		if buf := k.subnetBuffer[info.subnet]; buf != nil {
-			k.core.WriteTo(buf.packet, iwt.Addr(info.key[:]))
+			packets = append(packets, buf.packet)
 			delete(k.subnetBuffer, info.subnet)
 		}
-	} else {
-		k.resetTimeout(info)
-		k.mutex.Unlock()
+	}
+	k.resetTimeout(info)
+	k.mutex.Unlock()
+	for _, packet := range packets {
+		k.core.WriteTo(packet, iwt.Addr(info.key[:]))
 	}
 	return info
 }
diff --git a/src/multicast/multicast_darwin.go b/src/multicast/multicast_darwin.go
index e7075c0a..7ad0c543 100644
--- a/src/multicast/multicast_darwin.go
+++ b/src/multicast/multicast_darwin.go
@@ -1,3 +1,4 @@
+//go:build darwin
 // +build darwin
 
 package multicast
diff --git a/src/multicast/multicast_other.go b/src/multicast/multicast_other.go
index dfcf625f..9977951c 100644
--- a/src/multicast/multicast_other.go
+++ b/src/multicast/multicast_other.go
@@ -1,3 +1,4 @@
+//go:build !linux && !darwin && !netbsd && !freebsd && !openbsd && !dragonflybsd && !windows
 // +build !linux,!darwin,!netbsd,!freebsd,!openbsd,!dragonflybsd,!windows
 
 package multicast
diff --git a/src/multicast/multicast_unix.go b/src/multicast/multicast_unix.go
index 1ff48b17..9c822fcf 100644
--- a/src/multicast/multicast_unix.go
+++ b/src/multicast/multicast_unix.go
@@ -1,3 +1,4 @@
+//go:build linux || netbsd || freebsd || openbsd || dragonflybsd
 // +build linux netbsd freebsd openbsd dragonflybsd
 
 package multicast
diff --git a/src/multicast/multicast_windows.go b/src/multicast/multicast_windows.go
index 3666faaa..515412a4 100644
--- a/src/multicast/multicast_windows.go
+++ b/src/multicast/multicast_windows.go
@@ -1,3 +1,4 @@
+//go:build windows
 // +build windows
 
 package multicast
diff --git a/src/tuntap/tun_bsd.go b/src/tuntap/tun_bsd.go
index 75158857..fe36266b 100644
--- a/src/tuntap/tun_bsd.go
+++ b/src/tuntap/tun_bsd.go
@@ -1,3 +1,4 @@
+//go:build openbsd || freebsd
 // +build openbsd freebsd
 
 package tuntap
diff --git a/src/tuntap/tun_darwin.go b/src/tuntap/tun_darwin.go
index 75938881..6f6e2528 100644
--- a/src/tuntap/tun_darwin.go
+++ b/src/tuntap/tun_darwin.go
@@ -1,3 +1,4 @@
+//go:build !mobile
 // +build !mobile
 
 package tuntap
diff --git a/src/tuntap/tun_linux.go b/src/tuntap/tun_linux.go
index 0a845368..f849c00f 100644
--- a/src/tuntap/tun_linux.go
+++ b/src/tuntap/tun_linux.go
@@ -1,3 +1,4 @@
+//go:build !mobile
 // +build !mobile
 
 package tuntap
diff --git a/src/tuntap/tun_other.go b/src/tuntap/tun_other.go
index c0321267..8ce24953 100644
--- a/src/tuntap/tun_other.go
+++ b/src/tuntap/tun_other.go
@@ -1,3 +1,4 @@
+//go:build !linux && !darwin && !windows && !openbsd && !freebsd && !mobile
 // +build !linux,!darwin,!windows,!openbsd,!freebsd,!mobile
 
 package tuntap
diff --git a/src/tuntap/tun_windows.go b/src/tuntap/tun_windows.go
index 7b7ee710..8dce7274 100644
--- a/src/tuntap/tun_windows.go
+++ b/src/tuntap/tun_windows.go
@@ -1,3 +1,4 @@
+//go:build windows
 // +build windows
 
 package tuntap