def on_idle(op, *args)
      @idle_mutex.synchronize {
        @idle.insert(0, Act.new(op, args))
      }
      @loop.wakeup() if RUNNING == @state
    end
def on_idle(op, *args)
      @idle_mutex.synchronize {
        @idle.insert(0, Act.new(op, args))
      }
      @loop.wakeup() if RUNNING == @state
    end
Queues an operation and arguments to be called when the Actor is has no
 other requests to process.
 @param [Symbol] op method to queue for the Actor
 @param [Array] args arguments to the op method