Add docs for library instrumentation of RocketMQ remoting-based client (

open-telemetry#6960)

Fixes open-telemetry#6954

Co-authored-by: Fabrizio Ferri-Benedetti <[email protected]>
Co-authored-by: Trask Stalnaker <[email protected]>

instrumentation/rocketmq/rocketmq-client/rocketmq-client-4.8/README.md

@@ -1,4 +1,4 @@
-# Settings for the Apache RocketMQ client instrumentation
+# Settings for the Apache RocketMQ Remoting-based client instrumentation
 
 | System property | Type | Default | Description |
 |---|---|---|---|

instrumentation/rocketmq/rocketmq-client/rocketmq-client-4.8/library/README.md

@@ -0,0 +1,43 @@
+# Library Instrumentation for Apache RocketMQ Remoting-based Client 4.0.0+
+
+Provides OpenTelemetry instrumentation for [Apache RocketMQ](https://rocketmq.apache.org/) remoting-based client.
+
+## Quickstart
+
+### Add the following dependencies to your project:
+
+Replace `OPENTELEMETRY_VERSION` with the [latest release](https://search.maven.org/search?q=g:io.opentelemetry.instrumentation%20AND%20a:opentelemetry-rocketmq-client-4.8).
+
+For Maven, add the following to your `pom.xml` dependencies:
+
+```xml
+<dependencies>
+  <dependency>
+    <groupId>io.opentelemetry.instrumentation</groupId>
+    <artifactId>opentelemetry-rocketmq-client-4.8</artifactId>
+    <version>OPENTELEMETRY_VERSION</version>
+  </dependency>
+</dependencies>
+```
+
+For Gradle, add the following to your dependencies:
+
+```groovy
+implementation("io.opentelemetry.instrumentation:opentelemetry-rocketmq-client-4.8:OPENTELEMETRY_VERSION")
+```
+
+### Usage
+
+The instrumentation library provides the implementation of `SendMessageHook` and `ConsumeMessageHook` to provide OpenTelemetry-based spans and context propagation.
+
+```java
+RocketMqTelemetry rocketMqTelemetry;
+
+void configure(OpenTelemetry openTelemetry, DefaultMQProducerImpl producer, DefaultMQPushConsumerImpl pushConsumer) {
+  rocketMqTelemetry = RocketMqTelemetry.create(openTelemetry);
+  // For producer.
+  producer.registerSendMessageHook(rocketMqTelemetry.newTracingSendMessageHook());
+  // For push consumer.
+  pushConsumer.registerConsumeMessageHook(rocketMqTelemetry.newTracingConsumeMessageHook());
+}
+```