InteractionRequestMixins.cs

using System;
using System.Threading.Tasks;

namespace Microsoft.Practices.Prism.Interactivity.InteractionRequest
{
    public static class InteractionRequestMixins
    {
        public static async Task<T> RaiseAsync<T>(this InteractionRequest<T> request, T context) where T : INotification
        {
            return await AwaitCallbackResult<T>(callback => request.Raise(context, callback));
        }

        private static async Task<TResult> AwaitCallbackResult<TResult>(Action<Action<TResult>> f)
        {
            var tcs = new TaskCompletionSource<TResult>();
            f(n => tcs.SetResult(n));
            return await tcs.Task;
        }
    }
}