class Concurrent::Promises::AbstractEventFuture

def initialize(promise, default_executor)
  super()
  @Lock               = Mutex.new
  @Condition          = ConditionVariable.new
  @Promise            = promise
  @DefaultExecutor    = default_executor
  @Callbacks          = LockFreeStack.new
  @Waiters            = AtomicFixnum.new 0
  self.internal_state = PENDING
end