Function is_cancelled 

pub fn is_cancelled() -> bool

Returns true if the work running on the current thread was cancelled.

This reads the state of the innermost CancelOnDrop::scope on this thread, for example a blocking RPC call whose request was dropped because the client disconnected. Long running work should check this between units of work, such as transactions, and stop early since nobody waits for the result.

Always returns false outside of a CancelOnDrop::scope.