May be a duplicate of https://github.com/localstack/localstack/issues/988 but due to the age I will re raise.

I'm having issues when I throw an exception in a lambda - it isn't appearing on my dead letter queue. Is there something I am missing, I would like an sqs event exception to appear on the poison queue when an exception happens.

Below is the basic config:
 ````
    sqsclient.create_queue(QueueName = 'test-queue')
    sqsclient.create_queue(QueueName = 'test-queue-poison')

    lambda_client.create_function(
            FunctionName='MyFunction',
            Runtime='dotnetcore2.1',
            Role='role',
            Handler='Handler',
            Code=code,
	    DeadLetterConfig={'TargetArn': 'test-queue-poison-arn'})

     lambda_client.create_event_source_mapping(
		EventSourceArn='test-queue-arn',
		FunctionName='MyFunction',
		Enabled=True,
		BatchSize=100,
		StartingPosition='LATEST')
````

So when I raise a new (.net)exception within the lambda function no message is going to the dead letter queue. I can confirm that all is attached together OK as all other scenarios work, and the above code is pseudo-ish.
if is_alpine():
        
        return run('cp -r %s %s' % (source, target))
    shutil.copytree(source, target)
def rm_dir(dir):
    if is_alpine():
        
        return run('rm -r %s' % (dir))
    shutil.rmtree(dir)
def create_lambda_archive(script, get_content=False, libs=[], runtime=None, file_name=None):
    """ Utility method to create a Lambda function archive """
    runtime = runtime or LAMBDA_DEFAULT_RUNTIME
    tmp_dir = tempfile.mkdtemp(prefix=ARCHIVE_DIR_PREFIX)
    TMP_FILES.append(tmp_dir)
    file_name = file_name or get_handler_file_from_name(LAMBDA_DEFAULT_HANDLER, runtime=runtime)
    script_file = os.path.join(tmp_dir, file_name)
    if os.path.sep in script_file:
        mkdir(os.path.dirname(script_file))
        
        path = file_name.split(os.path.sep)
        for i in range(1, len(path)):
            save_file(os.path.join(tmp_dir, *(path[:i] + ['__init__.py'])), '')
    save_file(script_file, script)