McpClient.subscriptionsListen

Open a draft subscriptions/listen notification stream (draft basic/utilities/subscriptions). This replaces the removed resources/subscribe RPC and the standalone HTTP GET notification endpoint: it POSTs subscriptions/listen with a {notifications:{...}} filter (built from filter), the server upgrades the response to a long-lived text/event-stream, and this client reads it on a background task — delivering the leading notifications/subscriptions/acknowledged and every subsequent opted-in change notification to onNotification (and onProgress for progress). Returns a SubscriptionStream handle; call its cancel()/close() to stop listening and close the stream.

Only meaningful for draft servers (call enableModern/connect first); pre-draft servers do not implement subscriptions/listen.

class McpClient
@safe
subscriptionsListen