extensions/debug-server-ready/src/extension.ts/ServerReadyDetector/start
class ServerReadyDetector:	static start(session: vscode.DebugSession): ServerReadyDetector | undefined {
		if (session.configuration.serverReadyAction) {
			let detector = ServerReadyDetector.detectors.get(session);
			if (!detector) {
				detector = new ServerReadyDetector(session);
				ServerReadyDetector.detectors.set(session, detector);
			}
			return detector;
		}
		return undefined;
	}