Support set operation name in async mode span (#4015)

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/trace/EntrySpan.java

@@ -96,7 +96,7 @@ public class EntrySpan extends StackBasedTracingSpan {
 
     @Override
     public AbstractTracingSpan setOperationName(String operationName) {
-        if (stackDepth == currentMaxDepth) {
+        if (stackDepth == currentMaxDepth || isInAsyncMode) {
             return super.setOperationName(operationName);
         } else {
             return this;

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/trace/ExitSpan.java

@@ -116,7 +116,7 @@ public class ExitSpan extends StackBasedTracingSpan implements WithPeerInfo {
 
     @Override
     public AbstractTracingSpan setOperationName(String operationName) {
-        if (stackDepth == 1) {
+        if (stackDepth == 1 || isInAsyncMode) {
             return super.setOperationName(operationName);
         } else {
             return this;