Subscription handle returned by unified watch_* functions.
Carries enough state to send a matching unsubscribe frame via
Bourse.WS.unsubscribe/1.
Summary
Types
@type method() :: :watch_ticker | :watch_order_book | :watch_trades | :watch_orders
@type t() :: %Bourse.WS.Handle{ channels: [Bourse.WS.Subscription.channel()], exchange: Bourse.Exchange.t(), method: method(), opts: keyword() | map(), ws: Bourse.WS.t() }