Dependency injection on event hooks

Hi,

It would be good if we could inject arguments to event hook's constructor.

Below is my use case for that.

def create_app(config) -> App:
    client = StatsClient(config.stats_host, config.stats_port)

    app = App(
        components=[
            StatsComponent(client),
        ],
        event_hooks=[
            MetricHook
        ],
        routes=[
            Route('/', 'GET', views.home, name="index"),
        ])

    return app

class MetricHook:
    def __init__(self, client: StatsClient):
         self._client = client

    def on_response(self, route: Route):
        self._client.count("metric", 1)

encode / apistar

Dependency injection on event hooks #615