Reusing object instead of calling bean factory to retrieve it; fixes gh-905

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/annotation/SleuthAdvisorConfig.java

@@ -50,7 +50,7 @@ import org.springframework.util.StringUtils;
  * @since 1.2.0
  */
 @SuppressWarnings("serial")
-class SleuthAdvisorConfig  extends AbstractPointcutAdvisor implements BeanFactoryAware {
+class SleuthAdvisorConfig extends AbstractPointcutAdvisor implements BeanFactoryAware {
 
 	private Advice advice;
 

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/reactor/SpanSubscriptionProvider.java

@@ -34,6 +34,7 @@ class SpanSubscriptionProvider<T> implements Supplier<SpanSubscription<T>> {
 	final Subscriber<? super T> subscriber;
 	final Context context;
 	final String name;
+	private Tracing tracing;
 
 	SpanSubscriptionProvider(BeanFactory beanFactory,
 			Subscriber<? super T> subscriber,
@@ -45,11 +46,17 @@ class SpanSubscriptionProvider<T> implements Supplier<SpanSubscription<T>> {
 	}
 
 	@Override public SpanSubscription<T> get() {
-		Tracing tracing = this.beanFactory.getBean(Tracing.class);
-		return newCoreSubscriber(tracing);
+		return newCoreSubscriber(tracing());
 	}
 
 	SpanSubscription<T> newCoreSubscriber(Tracing tracing) {
 		return new SpanSubscriber<>(this.subscriber, this.context, tracing, this.name);
 	}
+
+	private Tracing tracing() {
+		if (this.tracing == null) {
+			this.tracing = this.beanFactory.getBean(Tracing.class);
+		}
+		return this.tracing;
+	}
 }