net40-client 
namespace 
{
    public static class AsyncCompatLibExtensions
    {
        public static Task<MetadataSet> GetMetadataAsync(this MetadataExchangeClient source, Uri address, MetadataExchangeClientMode mode);
    }
}
.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 net40-client
Assembly

Microsoft.CompilerServices.AsyncTargetingPack.Net4 , Version=1.0.0.0, PublicKeyToken=31bf3856ad364e35

Referencing

Your project needs a package reference to Microsoft.CompilerServices.AsyncTargetingPack.

Package Microsoft.CompilerServices.AsyncTargetingPack (1.0.1) net40
Platform Restrictions

This framework does not have platform annotations.

  • Built-in API
  • Package-provided API