Changing `ActionView._deque.maxlen` in subclasses

[glyg]

Is your feature request related to a problem? Please describe. I tried to lower the length of the ActionView _deque but could not find a way that would not result in a bug

Describe the solution you'd like

I would like to have a method to specify the ActionView queue length, ideally at the subclass definition level.

Describe alternatives you've considered I tried:

1. Changing the class attribute

class MyAction(ActionView):
    args = {
        "averages": fields.Integer(
            missing=20,
            example=20,
            description="Number of images to average over",
        )
    }
    # Marshal the response as a string representation of the array
    schema = fields.String()
    _deque = Deque(maxlen=10)
    ...

I believe this is rendered useless by the __init_subclass__ method.

2. Overwritting the _deque at init:

class MyAction(ActionView):
    args = {
        "averages": fields.Integer(
            missing=20,
            example=20,
            description="Number of images to average over",
        )
    }
    # Marshal the response as a string representation of the array
    schema = fields.String()
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._deque = Deque(maxlen=10)
    ...

This solution is causing the request to hang.

I also tried subclassing __init_subclass__ (?) but to no avail.

Thanks again for your work, sorry for the spam today :)