After adding Fiber#backtrace to rbx, we can see what each Fiber is doing!!

amazing-celluloid-stack-dumps.md

1 second has elapsed.

• The Actor thread is delivering the SyncCall message to the Task.
• The sleeping Task will be resumed in 2 seconds.
• The running Task (which is blocking using Kernel.sleep) will return in 1 second.

dump.txt

Celluloid::Actor 0x7400: Waiter
State: Running (executing tasks)
	gems/celluloid/lib/celluloid/tasks/task_fiber.rb:19:in `deliver'
	gems/celluloid/lib/celluloid/tasks.rb:69:in `resume'
	gems/celluloid/lib/celluloid/actor.rb:0:in `task'
	gems/celluloid/lib/celluloid/actor.rb:317:in `handle_message'
	gems/celluloid/lib/celluloid/actor.rb:174:in `run'
	gems/celluloid/lib/celluloid/actor.rb:157:in `initialize'
	gems/celluloid/lib/celluloid/thread_handle.rb:12:in `initialize'
	gems/celluloid/lib/celluloid/internal_pool.rb:63:in `create'

Tasks:
  1) Celluloid::TaskFiber: sleeping
	gems/celluloid/lib/celluloid/tasks/task_fiber.rb:14:in `signal'
	gems/celluloid/lib/celluloid/tasks.rb:59:in `suspend'
	gems/celluloid/lib/celluloid/tasks.rb:19:in `suspend'
	gems/celluloid/lib/celluloid.rb:60:in `suspend'
	gems/celluloid/lib/celluloid/actor.rb:308:in `sleep'
	gems/celluloid/lib/celluloid.rb:443:in `sleep'
	(pry):1:in `wait'
	gems/celluloid/lib/celluloid/calls.rb:25:in `dispatch'
	gems/celluloid/lib/celluloid/calls.rb:125:in `dispatch'
	gems/celluloid/lib/celluloid/actor.rb:326:in `handle_message'
	gems/celluloid/lib/celluloid/tasks.rb:42:in `initialize'
	gems/celluloid/lib/celluloid/tasks/task_fiber.rb:9:in `create'

  2) Celluloid::TaskFiber: running
	(pry):1:in `block'
	gems/celluloid/lib/celluloid/calls.rb:25:in `dispatch'
	gems/celluloid/lib/celluloid/calls.rb:125:in `dispatch'
	gems/celluloid/lib/celluloid/actor.rb:326:in `handle_message'
	gems/celluloid/lib/celluloid/tasks.rb:42:in `initialize'
	gems/celluloid/lib/celluloid/tasks/task_fiber.rb:9:in `create'

Fiber 0x73f8:
	gems/celluloid/lib/celluloid/stack_dump.rb:53:in `snapshot_thread'
	gems/celluloid/lib/celluloid/stack_dump.rb:30:in `snapshot'
	gems/celluloid/lib/celluloid/stack_dump.rb:26:in `snapshot'
	gems/celluloid/lib/celluloid/stack_dump.rb:22:in `initialize'
	gems/celluloid/lib/celluloid.rb:47:in `dump'
	(pry):1:in `__pry__'
	rbx/gems/1.9/gems/pry-0.9.12/lib/pry/pry_instance.rb:328:in `evaluate_ruby'
	rbx/gems/1.9/gems/pry-0.9.12/lib/pry/pry_instance.rb:278:in `re'
	rbx/gems/1.9/gems/pry-0.9.12/lib/pry/pry_instance.rb:254:in `rep'
	rbx/gems/1.9/gems/pry-0.9.12/lib/pry/pry_instance.rb:234:in `repl'
	rbx/gems/1.9/gems/pry-0.9.12/lib/pry/pry_instance.rb:232:in `repl'
	rbx/gems/1.9/gems/pry-0.9.12/lib/pry/pry_instance.rb:231:in `repl'
	rbx/gems/1.9/gems/pry-0.9.12/lib/pry/pry_instance.rb:230:in `repl'
	rbx/gems/1.9/gems/pry-0.9.12/lib/pry/pry_class.rb:170:in `start'
	rbx/gems/1.9/gems/pry-0.9.12/lib/pry/cli.rb:201:in `__script__'
	rbx/gems/1.9/gems/pry-0.9.12/lib/pry/cli.rb:70:in `parse_options'
	rbx/gems/1.9/gems/pry-0.9.12/lib/pry/cli.rb:70:in `parse_options'
	rbx/gems/1.9/gems/pry-0.9.12/bin/pry:16:in `__script__'
	rbx/gems/1.9/bin/pry:23:in `__script__'

Fiber 0x73fc:
	rbx/lib/19/timeout.rb:90:in `watch_channel'
	rbx/lib/19/timeout.rb:125:in `Timeout'

waiter.rb

class Waiter
  include Celluloid
  
  def wait
    sleep 3
  end
  
  def block
    Kernel.sleep(2)
  end
end

w = Waiter.new
w.async.wait
w.async.block
sleep 1
Celluloid.dump