net461 
namespace 
{
    public static class AsyncPlatformExtensions
    {
        public static Task SendTaskAsync(this SmtpClient smtpClient, MailMessage message);
    }
}
.NET Framework
4.04.54.5.14.5.24.64.6.14.6.24.74.7.14.7.24.84.8.1
Information specific to net461
Assembly

Microsoft.Threading.Tasks.Extensions.Desktop , Version=1.0.168.0, PublicKeyToken=b03f5f7f11d50a3a

Referencing

Your project needs a package reference to Microsoft.Bcl.Async.

Package Microsoft.Bcl.Async (1.0.168) net40
Platform Restrictions

This framework does not have platform annotations.

  • Built-in API
  • Package-provided API