如何处理ValueTask<T> 在 F# 中？

Question

So apparently .NET's brand new ValueTask<T> is the leaner version of Task<T> . That's cool, but if before I had to use Async.AwaitTask to integrate my F# Async workflows with Task, what should I do with ValueTask now?

Answer 1

在实现Async.AwaitValueTask之前（感谢 Aaron），可以使用 ValueTask 的AsTask方法， Async.AwaitTask使用Async.AwaitTask作为最简单的解决方案。

Answer 2

My OSS project "FusionTasks" can handle naturally and implicitly interprets both Task and ValueTask same as F# Async type on F# async workflow:

let asyncTest = async {
  use ms = new MemoryStream()

  // FusionTasks directly interpreted Task class in F# async-workflow block.
  do! ms.WriteAsync(data, 0, data.Length)
  do ms.Position <- 0L

  // FusionTasks directly interpreted Task<T> class in F# async-workflow block.
  let! length = ms.ReadAsync(data2, 0, data2.Length)
  do length |> should equal data2.Length
}

Answer 3

With the new task expressions, it is explained here: https://docs.microsoft.com/en-us/dotnet/fsharp/language-reference/task-expressions#value-tasks

I just implemented a System.IAsyncDisposable which returns a System.Threading.Tasks.ValueTask like so:

    interface IAsyncDisposable with
        member this.DisposeAsync(): ValueTask = 
            task {
                use _ = client
                return ()
            } |> ValueTask

You can see that I'm just piping the task to ValueTask .