OpenTelemetry Log4j appender does not handle non string values

When the Log4j LogEvent context data contains non string values e.g string arrays or java maps, the resulting attributes are incorrect.

Create a class extending ObjectThreadContextMap and set it as the default using the log4j system property log4j2.threadContextMap

Add the following code:

public class MyObjectContextMap implements ReadOnlyThreadContextMap, ObjectThreadContextMap {
//Implementation methods
}

In the logging code add the following

MyObjectContextMap map = (MyObjectContextMap)ThreadContext.getThreadContextMap();
map.putValue("numbers", new String[]{"one", "two", "three"});
HashMap testmap = new HashMap();
testmap.put("fn", "firstname");
testmap.put("ln", "lastname");
testmap.put(age, 25);
map.put("testmap", testmap);

logger.log(Level.TRACE, "test message");

What did you expect to see?
I would expect that the nested value and the array value would be included in attributes properly.

What did you see instead?
I saw the .toString() representations of the array and map. So numbers showed as an attribute with value [Ljava.lang.String and testmap showed up as a single value with the map values as {fn=firstname, ln=lastname}.

What version are you using?
1.23.0-alpha
Log4j: 2.17.1

No source file or test is named. Start by locating the OpenTelemetry Log4j appender and its handling of ThreadContext.getThreadContextMap(), then reproduce the example with the log4j2.threadContextMap system property. Done means array and map context values become proper nested attributes instead of Java toString representations.