Please address the comments from this code review:

## Individual Comments

### Comment 1
<location> `test/UnitTest/Utils/UtilityTest.cs:394-401` </location>
<code_context>
         var test1 = items.FirstOrDefault(i => i.Name == "Test-Null");
         Assert.NotNull(test1);
+
+#if NET9_0
+        Assert.Equal("", test1.Value);
+#elif NET10_0_OR_GREATER
         Assert.Equal("Test-Null", test1.Value);
+#endif

         var test2 = items.FirstOrDefault(i => i.Name == "Test-Key");
</code_context>

<issue_to_address>
**suggestion (testing):** Conditional assertions for different .NET versions may lead to inconsistent test coverage.

Ensure your CI pipeline runs tests for all supported .NET versions so these assertions are validated. Also, add a comment clarifying the version-specific behavior for maintainability.

```suggestion
        var test1 = items.FirstOrDefault(i => i.Name == "Test-Null");
        Assert.NotNull(test1);

        // NOTE: The expected value for test1.Value differs by .NET version:
        // - On .NET 9.0, Value is expected to be an empty string ("").
        // - On .NET 10.0 or greater, Value is expected to be "Test-Null".
        // Please ensure CI runs tests for all supported .NET versions so these assertions are validated.
#if NET9_0
        Assert.Equal("", test1.Value);
#elif NET10_0_OR_GREATER
        Assert.Equal("Test-Null", test1.Value);
#endif
```
</issue_to_address>

### Comment 2
<location> `test/UnitTest/Utils/UtilityTest.cs:405` </location>
<code_context>
         var test2 = items.FirstOrDefault(i => i.Name == "Test-Key");
         Assert.NotNull(test2);
-        Assert.Equal("Test-Key", test2.Value);
+        Assert.Equal("", test2.Value);

         option.UseKeyWhenValueIsNull = false;
</code_context>

<issue_to_address>
**suggestion (testing):** Test does not cover the scenario when both UseKeyWhenValueIsNull is false and the value is null.

Add assertions for when `UseKeyWhenValueIsNull` is false and the value is null to verify correct fallback or error handling.
</issue_to_address>

### Comment 3
<location> `test/UnitTest/Utils/UtilityTest.cs:408` </location>
<code_context>

         option.UseKeyWhenValueIsNull = false;
-        items = Utility.GetJsonStringByTypeName(option, this.GetType().Assembly, "UnitTest.Utils.UtilityTest", "en-US", true);
+        items = Utility.GetJsonStringByTypeName(option, GetType().Assembly, "UnitTest.Utils.UtilityTest", "en-US", true);

         test1 = items.FirstOrDefault(i => i.Name == "Test-Null");
</code_context>

<issue_to_address>
**suggestion (testing):** Consider adding negative test cases for invalid or missing keys.

Please include tests for scenarios where the key is missing, or its value is null or empty, to verify correct handling of these cases.

Suggested implementation:

```csharp
        test1 = items.FirstOrDefault(i => i.Name == "Test-Null");
        Assert.NotNull(test1);

        // Negative test: missing key
        var missingKey = items.FirstOrDefault(i => i.Name == "Test-Missing");
        Assert.Null(missingKey);

        // Negative test: key with null value
        var nullValueKey = items.FirstOrDefault(i => i.Name == "Test-ExplicitNull");
        if (nullValueKey != null)
        {
            Assert.Null(nullValueKey.Value);
        }

        // Negative test: key with empty value
        var emptyValueKey = items.FirstOrDefault(i => i.Name == "Test-Empty");
        if (emptyValueKey != null)
        {
            Assert.Equal("", emptyValueKey.Value);
        }

```

You may need to ensure that your test data (the JSON or source for `Utility.GetJsonStringByTypeName`) includes entries for "Test-ExplicitNull" and "Test-Empty" with appropriate values (null and empty string, respectively). If these do not exist, add them to your test data.
</issue_to_address>