(future-cancelled? f)
Returns true if future f is cancelled
user=> (def f (future (inc 0)))
#'user/f
user=> (future-cancel f)
false
user=> (future-cancelled? f)
false
user=> (future-done? f)
true
user=> @f
1
user=> (def f (future (Thread/sleep 5000) (inc 0)))
#'user/f
user=> (future-cancel f)
true
user=> (future-cancelled? f)
true
user=> (future-done? f)
true
user=> @f
java.util.concurrent.CancellationException (NO_SOURCE_FILE:0)