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_zip_file(zip_file_content):
        def execute(event, context):
            result, log_output = lambda_executors.EXECUTOR_LOCAL.execute_java_lambda(
                event, context, handler=handler, main_file=main_file)
            return result
        return execute, zip_file_content
    raise ClientError(error_response(
        'Unable to extract Java Lambda handler - file is not a valid zip/jar file', 400, error_type='ValidationError'))
def set_archive_code(code, lambda_name, zip_file_content=None):
    
    lambda_arn = func_arn(lambda_name)
    lambda_details = arn_to_lambda[lambda_arn]
    is_local_mount = code.get('S3Bucket') == BUCKET_MARKER_LOCAL
    if is_local_mount and config.LAMBDA_REMOTE_DOCKER:
        msg = 'Please note that Lambda mounts (bucket name "%s") cannot be used with LAMBDA_REMOTE_DOCKER=1'
        raise Exception(msg % BUCKET_MARKER_LOCAL)
    
    LAMBDA_EXECUTOR.cleanup(lambda_arn)
    if is_local_mount:
        
        
        
        
        return code['S3Key']
    
    zip_file_content = zip_file_content or get_zip_bytes(code)
    
    code_sha_256 = base64.standard_b64encode(hashlib.sha256(zip_file_content).digest())
    lambda_details.get_version('$LATEST')['CodeSize'] = len(zip_file_content)
    lambda_details.get_version('$LATEST')['CodeSha256'] = code_sha_256.decode('utf-8')