How to use the kafkajs.producers.forEach function in kafkajs

subscriptions = [{
                id: "step.one"  + timestamp ,
                event: "test.emit",
                emit: {
                    topic: "next",
                    event: "test.emit.received"
                }
            }];    
            service = broker.createService(Subscriber, Object.assign({ settings: { brokers: ["192.168.2.124:9092"], subscriptions: subscriptions } }));
            await broker.start();  
            let content = { 
                meta: opts.meta, 
                event: "test.emit",
                payload: { msg: "say hello to the world" },
            };
            producers.forEach(producer => { producer.fail = true; });
            mock.__emittedEventReset();
            try {
                await mock.__emit("events", 10, content);
            } catch (err) {
                expect(err.message).toBe("simulated fail of producer.send");
            }
            let emittedEvent = mock.__emittedEvent();    
            expect(emittedEvent).toEqual(null); 
        });