Use finalizeCleanup to avoid race conditions

library/src/main/java/com/frostnerd/vpntunnelproxy/VPNTunnelProxy.kt

@@ -265,8 +265,7 @@ open class VPNTunnelProxy(val packetProxy: PacketProxy,
             packetProxy.stop()
             cleanup()
             if(!proxyThreadActive) {
-                forwardedPacketStore?.clear(true)
-                forwardedPacketStore = null
+                finalizeCleanup()
             }
             tunnelHandle?.clear(true)
             tunnelHandle = null