I am trying to get Availability Zone provided the region information using .NET SDK but I am not able to get the exact same information which I can see on Azure while creating virtual machine from portal.

Following call returning me huge list of array where most of the entries are empty but few of them having [1 2 3]. Moreover, it takes alot of time.( around 10-12 seconds to bring the data )

        var connection = GetAzConnection(subscriptionId);
        List<string> ZoneInfo = new List<string>();
        var skus = connection.ComputeSkus.ListbyRegionAndResourceType(Region.Create(regionName),ComputeResourceType.VirtualMachines);
        foreach (IComputeSku sku in skus)
        {                
            var regionZones = sku.Zones;
            ZoneInfo.Add(RegionZoneToString(regionZones));
        }

While I am expecting just [ 1 2 3 ] against 'WesternEurope' for example.

Any idea how to get that corresponding info?

For reference, following code snippet.

Few regions where there are no zones information can be collected.