chore(exports): try calling heartbeat a bit more often (#16295)

* chore(exports): try calling heartbeat a bit more often

Looks like we end up rebalancing often. Possibly because we're not
sending the heartbeats in time and the session timing out.

* wip

* fix tests

plugin-server/src/main/ingestion-queues/batch-processing/each-batch.ts

@@ -47,7 +47,9 @@ export async function eachBatch(
             }
 
             const lastBatchMessage = messageBatch[messageBatch.length - 1]
-            await Promise.all(messageBatch.map((message: KafkaMessage) => eachMessage(message, queue)))
+            await Promise.all(
+                messageBatch.map((message: KafkaMessage) => eachMessage(message, queue).finally(() => heartbeat()))
+            )
 
             // this if should never be false, but who can trust computers these days
             if (lastBatchMessage) {

plugin-server/tests/main/ingestion-queues/each-batch.test.ts

@@ -131,15 +131,15 @@ describe('eachBatchX', () => {
 
     describe('eachBatch', () => {
         it('calls eachMessage with the correct arguments', async () => {
-            const eachMessage = jest.fn()
+            const eachMessage = jest.fn(() => Promise.resolve())
             const batch = createKafkaJSBatch(event)
             await eachBatch(batch, queue, eachMessage, groupIntoBatches, 'key')
 
             expect(eachMessage).toHaveBeenCalledWith({ value: JSON.stringify(event) }, queue)
         })
 
         it('tracks metrics based on the key', async () => {
-            const eachMessage = jest.fn()
+            const eachMessage = jest.fn(() => Promise.resolve())
             await eachBatch(createKafkaJSBatch(event), queue, eachMessage, groupIntoBatches, 'my_key')
 
             expect(queue.pluginsServer.statsd.timing).toHaveBeenCalledWith(