Segfault in e2e/groups.spec.js

**Environment Information**
- OS: MacOS 15.1
- Node Version: 20.18
- NPM Version: 10.18.2
- C++ Toolchain: llvm
- confluent-kafka-javascript version: 377e22ab7e86ce6b0bffc06d3a6deb573d51288b

**Steps to Reproduce**

```
$ npx mocha --timeout 120000 e2e/groups.spec.js

Consumer group/Producer
[1] 13601 segmentation fault npx mocha --timeout 120000 e2e/
```

Here's the stack trace:

```c++
llnode -- node ./node_modules/.bin/mocha --timeout 120000 e2e/groups.spec.js
(lldb) target create "node"
Current executable set to '/opt/node-debug/bin/node' (arm64).
(lldb) settings set -- target.run-args "./node_modules/.bin/mocha" "--timeout" "120000" "e2e/groups.spec.js"
(lldb) plugin load '/Users/trevor/.nvm/versions/node/v20.18.0/lib/node_modules/llnode/llnode.dylib'
(lldb) settings set prompt '(llnode) '
(llnode) r
Process 11240 launched: '/opt/node-debug/bin/node' (arm64)

Consumer group/Producer
Process 11240 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
frame #0: 0x0000000128807018 confluent-kafka-javascript.node`Nan::Callback::Call_(v8::Isolate*, v8::Local, int, v8::Local*, Nan::AsyncResource*) const [inlined] v8::Local::New(isolate=0x0000000140008000, that=0x0000000000000000) at v8-local-handle.h:287:68 [opt]
284
285 V8_INLINE static Local New(Isolate* isolate,
286 const PersistentBase& that) {
-> 287 return New(isolate, internal::ValueHelper::SlotAsValue(that.val_));
288 }
289
290 V8_INLINE static Local New(Isolate* isolate,
warning: confluent-kafka-javascript.node was compiled with optimization - stepping may behave oddly; variables may not be available.
(llnode) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
* frame #0: 0x0000000128807018 confluent-kafka-javascript.node`Nan::Callback::Call_(v8::Isolate*, v8::Local, int, v8::Local*, Nan::AsyncResource*) const [inlined] v8::Local::New(isolate=0x0000000140008000, that=0x0000000000000000) at v8-local-handle.h:287:68 [opt]
frame #1: 0x0000000128807018 confluent-kafka-javascript.node`Nan::Callback::Call_(v8::Isolate*, v8::Local, int, v8::Local*, Nan::AsyncResource*) const [inlined] v8::Local Nan::New>(p=0x0000000000000000) at nan_implementation_12_inl.h:422:10 [opt]
frame #2: 0x0000000128807014 confluent-kafka-javascript.node`Nan::Callback::Call_(this=0x0000000000000000, isolate=, target=(val_ = 0x000000013800aee8), argc=4, argv=0x000000016fdf6968, resource=0x000000016fdf68a0) const at nan.h:1880:36 [opt]
frame #3: 0x0000000128802fac confluent-kafka-javascript.node`Nan::Callback::Call(this=0x0000000000000000, argc=4, argv=0x000000016fdf6968) const at nan.h:1824:25 [opt]
frame #4: 0x0000000128825a54 confluent-kafka-javascript.node`NodeKafka::Workers::KafkaConsumerConsumeLoop::HandleMessageCallback(this=0x000000014f708810, msg=0x00006000023a8d80, ec=) at workers.cc:775:13 [opt]
frame #5: 0x0000000128829e90 confluent-kafka-javascript.node`NodeKafka::Workers::MessageWorker::WorkMessage(this=0x000000014f708810) at workers.h:110:7 [opt]
frame #6: 0x0000000100b88d08 node`uv__async_io(loop=0x00000001041d4c90, w=, events=) at async.c:176:5 [opt]
frame #7: 0x0000000100b9b9b0 node`uv__io_poll(loop=0x00000001041d4c90, timeout=0) at kqueue.c:381:9 [opt]
frame #8: 0x0000000100b89270 node`uv_run(loop=0x00000001041d4c90, mode=UV_RUN_DEFAULT) at core.c:447:5 [opt]
frame #9: 0x0000000100005818 node`node::SpinEventLoopInternal(env=0x0000000138018c00) at embed_helpers.cc:41:7 [opt]
frame #10: 0x00000001001347ac node`node::NodeMainInstance::Run(this=, exit_code=0x000000016fdff184, env=0x0000000138018c00) at node_main_instance.cc:124:9 [opt]
frame #11: 0x00000001001344b8 node`node::NodeMainInstance::Run(this=) at node_main_instance.cc:100:3 [opt]
frame #12: 0x00000001000b02c4 node`node::Start(int, char**) [inlined] node::StartInternal(argc=, argv=) at node.cc:1502:24 [opt]
frame #13: 0x00000001000b01d4 node`node::Start(argc=, argv=) at node.cc:1509:27 [opt]
frame #14: 0x00000001863b4274 dyld`start + 2840
```

(This even occurs with a fix for #161.)