// Alias namespaces to make code shorter/easier to read
var netinfo = System.Net.NetworkInformation;
var netint = System.Net.NetworkInformation.NetworkInterface;

if (netint.GetIsNetworkAvailable())
{
    StrokesPlus.Console.Log("Checking network speed for all interfaces...\n");
    var output = "\n";
    var interfaces = netint.GetAllNetworkInterfaces();

    // For each network interface
    for (var ni = 0; ni < interfaces.Length; ni++) {   

        // Only those which are up, not tunnel, and not local loopback
        if(interfaces[ni].OperationalStatus == netinfo.OperationalStatus.Up
           && interfaces[ni].NetworkInterfaceType != netinfo.NetworkInterfaceType.Tunnel 
           && interfaces[ni].NetworkInterfaceType != netinfo.NetworkInterfaceType.Loopback) 
        {
            var adapter = interfaces[ni].GetIPProperties(); 
            var addresses = adapter.UnicastAddresses.ToArray();

            // If there are no unicast addresses, move to next
            if(addresses.Length == 0) {
                continue;
            }
            output += "----------------------------------------------------\n";
            
            //Print connection name and IP
            output += `Name: ${interfaces[ni].Description}\n`;
            for (var ip = 0; ip < addresses.Length; ip++)
            {
                if (addresses[ip].Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
                {
                    output += `IP: ${addresses[ip].Address.ToString()}\n`;
                }
            }

            // Get sent/received byte data
            var netstats = interfaces[ni].GetIPv4Statistics();
            var startBytesSent = netstats.BytesSent;
            var startBytesRec = netstats.BytesReceived;

            //Wait 1 second to compare results for speed
            sp.Pause(1);

            // Get latest sent/receieved bytes and calculate/format speed
            netstats = interfaces[ni].GetIPv4Statistics();

            //Convert total bytes to KB and add commas for large numbers
            var bytesSentFormatted = (netstats.BytesSent / 1024).toFixed(0).toString().replace(/\B(?=(\d{3})+(?!\d))/g, ',');
            var bytesReceivedFormatted = (netstats.BytesReceived / 1024).toFixed(0).toString().replace(/\B(?=(\d{3})+(?!\d))/g, ',');

            //Calculate speed in KB/s, only to last 2 decimals
            var bytesSentSpeedFormatted = ((netstats.BytesSent - startBytesSent) / 1024).toFixed(2);
            var bytesReceivedSpeedFormatted = ((netstats.BytesReceived - startBytesRec) / 1024).toFixed(2);

            //Print formatted bytes/speed
            output += `Bytes Sent: ${bytesSentFormatted} KB (${bytesSentSpeedFormatted} KB/s)\n`;
            output += `Bytes Received: ${bytesReceivedFormatted} KB (${bytesReceivedSpeedFormatted} KB/s)\n`;
        }
    }

    StrokesPlus.Console.Log(output);
}

2021-12-06 09:51:48.72: Checking network speed for all interfaces...

2021-12-06 09:51:51.81: 
----------------------------------------------------
Name: Killer E2500 Gigabit Ethernet Controller
IP: 192.168.1.121
Bytes Sent: 2,133,277,477 KB (14.13 KB/s)
Bytes Received: 260,396,937 KB (34.24 KB/s)
----------------------------------------------------
Name: VMware Virtual Ethernet Adapter for VMnet1
IP: 192.168.68.1
Bytes Sent: 338 KB (0.00 KB/s)
Bytes Received: 0 KB (0.00 KB/s)
----------------------------------------------------
Name: VMware Virtual Ethernet Adapter for VMnet8
IP: 192.168.37.1
Bytes Sent: 341 KB (0.00 KB/s)
Bytes Received: 95 KB (0.00 KB/s)