MWA Set environment variable on ApplicationPool

Program.cs

using Microsoft.Web.Administration;

namespace MWASample
{
    public class Program
    {
        static void Main(string[] args)
        {
            var serverManager = new ServerManager();
            var config = serverManager.GetApplicationHostConfiguration();
            var section = config.GetSection("system.applicationHost/applicationPools");
            var collection = section.GetCollection();

            var DefaultAppPool = collection[0];
            var envVariables = DefaultAppPool.GetChildElement("environmentVariables").GetCollection();

            var newElement = envVariables.CreateElement();
            newElement.SetAttributeValue("name", "FOO");
            newElement.SetAttributeValue("value", "BAR");
            envVariables.Add(newElement);
            serverManager.CommitChanges();

        }
    }
}