The subnet identifier for the Amazon VPC connection, if applicable. You can specify several subnets in a comma-separated list. When you
specify VPCZoneIdentifier with AvailabilityZones, ensure that the subnets' Availability Zones match the values you specify for
AvailabilityZones. For more information on creating your Auto Scaling group in Amazon VPC by specifying subnets, see Launch Auto Scaling Instances into Amazon
VPC in the the Auto Scaling Developer Guide.
Constraints:

C# |
public string VPCZoneIdentifier { get; set; }