The .NET Framework 4 introduces a new mechanism for cancellation of operations, based on new types CancellationToken and CancellationTokenSource. This cancellation mechanism is used across the parallel programming libraries: tasks, concurrent collections, and PLINQ queries.

Using Cancellation Support in .NET Framework 4, written by Mike Liddell, is an in-depth exploration of CancellationToken and CancellationTokenSource, how to make use of the cancellation support, and what are the common usage patterns that arise in practice.

(This paper and many more are available through the Parallel Computing Developer Center on MSDN at http://msdn.microsoft.com/en-us/concurrency/ee851578.aspx.)