chore: address PR feedback

Author: AllanZhengYP

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/AddEventStreamSigningDependency.java

@@ -102,10 +102,7 @@ public Map<String, Consumer<TypeScriptWriter>> getRuntimeConfigWriters(
         }
     }
 
-    private static boolean hasEventStreamInput(
-            Model model,
-            ServiceShape service
-    ) {
+    private static boolean hasEventStreamInput(Model model, ServiceShape service) {
         TopDownIndex topDownIndex = model.getKnowledge(TopDownIndex.class);
         Set<OperationShape> operations = topDownIndex.getContainedOperations(service);
         EventStreamIndex eventStreamIndex = model.getKnowledge(EventStreamIndex.class);

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/AwsRestXml.java

@@ -207,9 +207,9 @@ protected void serializeInputPayload(
             writer.write("contents = $L;",
                     getInputValue(context, Location.PAYLOAD, "input." + memberName, member, target));
 
-            // Structure and Union payloads will serialize as XML documents via XmlNode.
+            // Structure and Union payloads that's not events stream will serialize as XML documents via XmlNode.
             if ((target instanceof StructureShape || target instanceof UnionShape)
-                    && member.hasTrait(EventStreamTrait.class)) {
+                    && !member.hasTrait(EventStreamTrait.class)) {
                 // Start with the XML declaration.
                 writer.write("body = \"<?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?>\";");
 

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/RestJsonProtocolGenerator.java

@@ -147,11 +147,11 @@ protected void serializeInputPayload(
         MemberShape payloadMember = payloadBinding.getMember();
         Shape target = context.getModel().expectShape(payloadMember.getTarget());
 
-        // When payload is not event stream and the target is a structure or union, default to an
-        // empty JSON body instead of an undefined body and make sure any structure or union
+        // When payload target is a structure or union but payload is not an event stream, default
+        // to an empty JSON body instead of an undefined body and make sure any structure or union
         // content ends up as a JSON string.
-        if (!payloadMember.hasTrait(EventStreamTrait.class)
-                && (target instanceof StructureShape || target instanceof UnionShape)) {
+        if ((target instanceof StructureShape || target instanceof UnionShape)
+                && !payloadMember.hasTrait(EventStreamTrait.class)) {
             writer.openBlock("if (body === undefined) {", "}", () -> writer.write("body = {};"));
             writer.write("body = JSON.stringify(body);");
         }