update kafka client usage example

Author: jaydeluca

instrumentation/spring/spring-kafka-2.7/library/README.md

@@ -1,7 +1,7 @@
 # Library Instrumentation for Spring Kafka version 2.7 and higher
 
 Provides OpenTelemetry instrumentation for [Spring Kafka](https://spring.io/projects/spring-kafka),
-enabling consumer messaging spans for Spring Kafka listeners
+enabling consumer and producer messaging spans.
 
 ## Quickstart
 
@@ -30,26 +30,38 @@ implementation("io.opentelemetry.instrumentation:opentelemetry-spring-kafka-2.7:
 ### Usage
 
 The instrumentation library provides interceptors that can be added to Spring Kafka message
-listener containers to provide OpenTelemetry-based spans and context propagation.
+listener containers and producers to provide spans and context propagation.
 
 ```java
 import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.instrumentation.kafkaclients.v2_6.KafkaTelemetry;
 import io.opentelemetry.instrumentation.spring.kafka.v2_7.SpringKafkaTelemetry;
+import org.springframework.boot.autoconfigure.kafka.DefaultKafkaProducerFactoryCustomizer;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.kafka.config.ContainerCustomizer;
 import org.springframework.kafka.listener.ConcurrentMessageListenerContainer;
 
-public class SpringKafkaConfiguration {
+@Configuration
+public class KafkaInstrumentationConfig {
 
-  // Use this ContainerCustomizer to add interceptors to your Kafka listener containers.
+  // Instrument Kafka producers
+  @Bean
+  public DefaultKafkaProducerFactoryCustomizer producerInstrumentation(
+      OpenTelemetry openTelemetry) {
+    KafkaTelemetry kafkaTelemetry = KafkaTelemetry.create(openTelemetry);
+    return producerFactory -> producerFactory.addPostProcessor(kafkaTelemetry::wrap);
+  }
+
+  // Instrument Kafka consumers
+  @Bean
   public ContainerCustomizer<String, String, ConcurrentMessageListenerContainer<String, String>>
-      createListenerCustomizer(OpenTelemetry openTelemetry) {
-    SpringKafkaTelemetry telemetry = SpringKafkaTelemetry.builder(openTelemetry).build();
+      listenerCustomizer(OpenTelemetry openTelemetry) {
+    SpringKafkaTelemetry springKafkaTelemetry = SpringKafkaTelemetry.create(openTelemetry);
     return container -> {
-      container.setRecordInterceptor(telemetry.createRecordInterceptor());
-      container.setBatchInterceptor(telemetry.createBatchInterceptor());
+      container.setRecordInterceptor(springKafkaTelemetry.createRecordInterceptor());
+      container.setBatchInterceptor(springKafkaTelemetry.createBatchInterceptor());
     };
   }
-
-  // Configure the customizer in your Spring Kafka configuration.
 }
 ```