在尝试捕获中未捕获异步任务异常

Question

我试图通过调用Socket.ReceiveAsync()并处理不可避免的Socket.Close()来取消SocketException通话。

我的问题是调用函数中的异常似乎从未出现在try/catch中。像这样：

public async Task DoSomethingAsync()
{
    Try
    {
        while(true)
        {
            await DoSomethingMoreSpecificAsync();
            ....
        }
    }
    catch(Exception ex)
    {
        do some logging... <-- exception never makes it here
    }
    finally
    {
        cleanup stuff();  <-- or here...
    }
}

public async Task DoSomethingMoreSpecificAsync()
{
    var read = await _sock.ReceiveAsync(...); <-- Exception is thrown here
}

因此，引发异常时，应用程序永远不会将其置于catch或finally块中。它只是抱怨未处理的异常。 AFAIK async Task方法应像其他任何方法一样向上传播其异常。我知道如果我使用async void ...

在控制台中，应用崩溃后，我看到以下内容：

  在抛出“ PAL_SEHException”实例后调用

terminate

这是实际代码：

private async Task DoReceiveAsync()
{
    var writer = _inputPipe.Writer;
    Exception ex = null;

    try
    {
        while (true)
        {
            var mem = writer.GetMemory(TLS_MAX_RECORD_SIZE);
            MemoryMarshal.TryGetArray(mem, out ArraySegment<byte> buf);

            //Since OpenSSL will only gve us a complete record, we need a func that will piece one back together from the stream
            await ReadRecord(mem); 

            var res = _ssl.Read(buf.Array, TLS_MAX_RECORD_SIZE);

            writer.Advance(res);

            var flush = await writer.FlushAsync();

            if (flush.IsCanceled || flush.IsCompleted)
                break;
        }
    }
    catch (Exception e) { ex = e; }
    finally { writer.Complete(ex); }
}

private async Task ReadRecord(Memory<byte> mem)
{
    MemoryMarshal.TryGetArray(mem, out ArraySegment<byte> buf);

    SslError res;

    do
    {
        var sockRead = await _socket.ReceiveAsync(buf, SocketFlags.None);

        if (sockRead == 0) break;

        _ssl.ReadBio.Write(buf.Array, sockRead);
        var sslRead = _ssl.Peek(peekBuf, TLS_MAX_RECORD_SIZE);

        res = _ssl.GetError(sslRead);

    } while (res != SslError.SSL_ERROR_NONE);

    return;
}