add short explanation in javadoc

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/ribbon/RibbonClientConfiguration.java

@@ -88,8 +88,17 @@ public class RibbonClientConfiguration {
 		return serverList;
 	}
 
+	/**
+	 * Create a Netflix {@link RestClient} integrated with Ribbon if none already exists in the
+	 * application context. It is not required for Ribbon to work properly and is therefore  
+	 * created lazily if ever another component requires it.
+	 * 
+	 * @param config the configuration to use by the underlying Ribbon instance
+	 * @param loadBalancer the load balancer to use by the underlying Ribbon instance
+	 * @return a {@link RestClient} instances backed by Ribbon
+	 */
 	@Bean
-	@Lazy // see https://github.com/spring-cloud/spring-cloud-netflix/issues/312
+	@Lazy
 	@ConditionalOnMissingBean
 	public RestClient ribbonRestClient(IClientConfig config, ILoadBalancer loadBalancer) {
 		RestClient client = new OverrideRestClient(config);