Answered: SFtp GetFileAsync and task.Wait() call is blocked.

EndGetFile of 'A' Task is blocked like the above example.
This may be a limitation of the Async function.
In another test,
Using single SFTP connection
There is no way for the AbortTransfer () function to cancel a specific GetFile when calling GetFile () on each thread.
I still can not solve the problem of cancellation of download / upload in case of single SFTP Connect.
I tried using SFTP Bind.
In this case, the AbortTransfer () function works because each SFTP Instance is used.
However, if I do a lot of Bind, I will get a Bind failure.
Is there a good way to cancel a transfer?