@Incubating public interface CancellationTokenSource
CancellationTokenSourceallows you to issue cancellation requests to one or more
LongRunningOperationinstances. To use a token source:
LongRunningOperation.withCancellationToken(CancellationToken). You need to do this before you start the operation.
cancel()on this token source.
All implementations of this interface are required to be thread safe.
It is assumed that the implementation will do 'best-effort' attempt to perform cancellation.
This method returns immediately and if the cancellation is successful the cancelled operation
will notify its
BuildCancelledException describing how it was cancelled.
CancellationTokenSource. Always returns the same instance.