using System.Threading.Tasks;
public static void Main()
Console.WriteLine("press 'e' key to email everybody");
while (Console.ReadLine().ToLower() == "e")
Console.WriteLine("... e pressed for email to say 'Hi Bob'");
public async static void startEmail()
Console.WriteLine("... started email");
await EmailAsync("Hi Bob", EmailCompleted);
private static async Task EmailAsync(string message, Action<string> callback)
Console.WriteLine("... sending email, message is " + message);
public static void EmailCompleted(string message)
Console.WriteLine(message + "sent as email");
public static void Jack()
Console.WriteLine("Jack!");