module Async
module Kernel
class Async::Barrier
class Async::Barrier::TaskNode
class Async::Children
class Async::Clock
class Async::Condition
class Async::Condition::FiberNode
class Async::LimitedQueue
class Async::List
class Async::List::Iterator
class Async::List::Node
class Async::Node
class Async::Notification
class Async::Queue
class Async::Reactor
class Async::Scheduler
class Async::Scheduler::ClosedError
class Async::Semaphore
class Async::Semaphore::FiberNode
class Async::Stop
class Async::Stop::Later
class Async::Task
class Async::Task::FinishedError
class Async::TimeoutError
class Async::Variable
class Async::Waiter
class Async::Wrapper
class Async::Wrapper::Cancelled
async
2.6.2
# nil?
def nil? empty? end