ref(samples): Clarify Kafka consumer tracing sample

Print the consumed Kafka record inside the manual consumer tracing callback so the sample shows where application processing happens. Update the console system test to assert the manual queue.process transaction and its manual consumer origin.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: adinauer

sentry-samples/sentry-samples-console/src/main/java/io/sentry/samples/console/kafka/KafkaShowcase.java

@@ -112,7 +112,16 @@ private static Thread startConsumerWithSentryTracing(
                   final ConsumerRecords<String, String> records =
                       consumer.poll(Duration.ofMillis(500));
                   for (final ConsumerRecord<String, String> record : records) {
-                    SentryKafkaConsumerTracing.withTracing(record, consumedLatch::countDown);
+                    SentryKafkaConsumerTracing.withTracing(
+                        record,
+                        () -> {
+                          System.out.println(
+                              "Consumed Kafka message from "
+                                  + record.topic()
+                                  + ": "
+                                  + record.value());
+                          consumedLatch.countDown();
+                        });
                     if (consumedLatch.getCount() == 0) {
                       break;
                     }

sentry-samples/sentry-samples-console/src/test/kotlin/io/sentry/systemtest/ConsoleApplicationSystemTest.kt

@@ -42,7 +42,8 @@ class ConsoleApplicationSystemTest {
     }
 
     testHelper.ensureTransactionReceived { transaction, _ ->
-      testHelper.doesTransactionHaveOp(transaction, "queue.receive") &&
+      testHelper.doesTransactionHaveOp(transaction, "queue.process") &&
+        transaction.contexts.trace?.origin == "manual.queue.kafka.consumer" &&
         transaction.contexts.trace?.data?.get("messaging.system") == "kafka"
     }
   }