GH-1198 Fix tracibility wrapper

Fix tracibility wrapper to ensure traceid/spanid are captured on subsequent invocations

Resolves #1198

Author: olegz

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/FunctionAroundWrapper.java

@@ -16,8 +16,6 @@
 
 package org.springframework.cloud.function.context.catalog;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.reactivestreams.Publisher;
 
 import org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry.FunctionInvocationWrapper;
@@ -37,14 +35,15 @@
  */
 public abstract class FunctionAroundWrapper {
 
-	private static final Log log = LogFactory.getLog(FunctionAroundWrapper.class);
-
 	public final Object apply(Object input, FunctionInvocationWrapper targetFunction) {
+
 		String functionalTracingEnabledStr = System.getProperty("spring.cloud.function.observability.enabled");
 		boolean functionalTracingEnabled = !StringUtils.hasText(functionalTracingEnabledStr)
 				|| Boolean.parseBoolean(functionalTracingEnabledStr);
 		if (functionalTracingEnabled && !(input instanceof Publisher) && input instanceof Message && !FunctionTypeUtils.isCollectionOfMessage(targetFunction.getOutputType())) {
-			return this.doApply(input, targetFunction);
+			Object result = this.doApply(input, targetFunction);
+			targetFunction.wrapped = false;
+			return result;
 		}
 		else {
 			return targetFunction.apply(input);

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java

@@ -417,7 +417,7 @@ public class FunctionInvocationWrapper implements Function<Object, Object>, Cons
 
 		private boolean propagateInputHeaders;
 
-		private boolean wrapped;
+		protected boolean wrapped;
 
 		private final ThreadLocal<Message<Object>> unconvertedResult = new ThreadLocal<>();