Task.WaitAll Method (Task, CancellationToken)
Waits for all of the provided Task objects to complete execution unless the wait is cancelled.
Assemblies: System.Threading.Tasks (in System.Threading.Tasks.dll)
mscorlib (in mscorlib.dll)
static member WaitAll : tasks:Task * cancellationToken:CancellationToken -> unit
The cancellationToken was canceled.
The tasks argument is a null reference (Nothing in Visual Basic).
An exception was thrown during the execution of at least one of the Task instances.
The tasks argument contains a null element.
One or more of the Task objects in tasks has been disposed.
The cancellationToken argument is used to cancel the wait operation. Cancellation of the tasks is a distinct operation, and is signaled by the AggregateException as noted above.