middlewares should be triggered also on binding

[FabienArcellier]

Middlewares trigger exclusively on events that are explicitly attached. If a variable is bound, they are not triggered. It's not practical.

Here is the example of a weather station where I would like to write a file with the state each time a variable changes. I have to explicitly attach an event handler for the middleware mechanism to work.

import io
import json

import writer as wf

@wf.middleware()
def on_change(state: wf.WriterState):
    yield

    with io.open("weather.json", "w") as f:
        f.write(json.dumps(state.to_dict()))

# I have to attach this event handler. 
# I would prefer to trigger on any event
def on_trigger():
    pass

initial_state = wf.init_state({
    "outside_atmospheric_pressure_now": 1026.0,
    "outside_humidity": 0,
    "outside_wind_speed": 0,
    "outside_temperature": 22
})

---

@wf.middleware(event_handler=True, binding=True)  # default
@wf.middleware(binding=False)