public async Task UpdateValueTest()
{
var revision = 0;
async Task <int> update()
{
var r = Interlocked.Increment(ref revision);
await Task.Delay(10);
return(r);
}
var asyncCache = new AsyncCache <int>(update);
await asyncCache.Task;
var result = await asyncCache.UpdateAsync();
Assert.AreEqual(revision, result);
}