src/vs/workbench/api/browser/mainThreadDebugService.ts/MainThreadDebugService/$customDebugAdapterRequest
class MainThreadDebugService:	public $customDebugAdapterRequest(sessionId: DebugSessionUUID, request: string, args: any): Promise<any> {
		const session = this.debugService.getModel().getSession(sessionId, true);
		if (session) {
			return session.customRequest(request, args).then(response => {
				if (response && response.success) {
					return response.body;
				} else {
					return Promise.reject(new Error(response ? response.message : 'custom request failed'));
				}
			});
		}
		return Promise.reject(new Error('debug session not found'));
	}