NEPacketTunnelProvider: Not able to read packets from the virtual interface

Here is my code snippet,

setTunnelNetworkSettings(networkSettings, completionHandler: { (error) -> Void in
            if (error != nil) {
                NSLog("Failed to apply network settings: \(String(describing: error))")
                completionHandler(error)
            } else {
                NSLog("Successfully applied network settings")
                completionHandler(error)

                    //Read packets from the interface
                    let packetFlow =  NEPacketTunnelFlow()
                    packetFlow.readPackets(completionHandler: {packets_array, protocols_array in
                        NSLog("Packets read from virtual interface, packets_array: \(packets_array.count), protocol_array has: \(protocols_array.count) entries")
                    })
                    //Read packets done
              
            }
        })

In order to test this flow, I start the traffic first and then bring up my application.
But I am not able to read any packets from the virtual interface.
This is what I see in the logs:

Packets read from virtual interface, packets_array: 0, protocol_array has: 0 entries

Can someone please let me know if I am missing something here?
Thank you.

Thank you for the reply eskimo!
That made it work. I am able to read packets now.
But I see there is a default route that is always created even if there is no route configured in the PacketTunnelProvider,
Here is the output of my "netstat -nr" command:

Internet:
Destination        Gateway            Flags        Netif Expire
default            192.168.1.1        UGSc           en0      
default            link#18            UCSI         utun2  

Is the entry at line #4 supposed to be present even if no default route is configured over the utun interface?
Thank you.

Interpreting the routing table on Apple platforms can be tricky. My general advice is that you not go down that path unless you have a routing problem. So, regardless of what

netstat

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—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Thank you for the response Eskimo!
I dont have a routing problem. PacketTunnelProvider is working as expected.