plugins.rb

require 'celluloid'

class PluginOne
  include Celluloid

  def foo(args)
    args[:first_added] = true
    yield :continue
  end
end

class PluginTwo
  include Celluloid

  def foo(args)
    args[:second_added] = true
    yield :stop # third plugin will never see the event
  end
end

class PluginThird
  include Celluloid

  def foo(args)
    yield :continue
  end
end

class Manager
  include Celluloid

  def initialize
    @plugins = [PluginOne.new, PluginTwo.new, PluginThird.new]
  end

  def process(events)
    events.each do |event, args|
      actor = Celluloid.current_actor
      @plugins.each do |plugin|
        plugin.send "#{event}!", args do |status|
          actor.mailbox << PluginStatus.new(status)
        end
        args = args.dup # avoid action at a distance
        message = receive { |m| m.is_a? PluginStatus }
        p args
        puts message.type
        break if message.type == :stop
      end
    end
  end
end

class PluginStatus
  attr_accessor :type
  def initialize(type)
    @type = type
  end
end

manager = Manager.new
manager.process({ foo: {} })