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.
result = self.lambda_client.invoke(
            FunctionName=TEST_LAMBDA_NAME_JAVA, Payload=b'{}')
        result_data = result['Payload'].read()
        self.assertEqual(result['StatusCode'], 200)
        self.assertIn('LinkedHashMap', to_str(result_data))
    def test_java_runtime_with_lib(self):
        java_jar_with_lib = load_file(TEST_LAMBDA_JAVA_WITH_LIB, mode='rb')
        
        jar_dir = new_tmp_dir()
        zip_dir = new_tmp_dir()
        unzip(TEST_LAMBDA_JAVA_WITH_LIB, jar_dir)
        shutil.move(os.path.join(jar_dir, 'lib'), os.path.join(zip_dir, 'lib'))
        jar_without_libs_file = testutil.create_zip_file(jar_dir)
        shutil.copy(jar_without_libs_file, os.path.join(zip_dir, 'lib', 'lambda.jar'))
        java_zip_with_lib = testutil.create_zip_file(zip_dir, get_content=True)
        for archive in [java_jar_with_lib, java_zip_with_lib]:
            lambda_name = 'test-%s' % short_uid()
            testutil.create_lambda_function(func_name=lambda_name,
                zip_file=archive, runtime=LAMBDA_RUNTIME_JAVA8,
                handler='cloud.localstack.sample.LambdaHandlerWithLib')
            result = self.lambda_client.invoke(FunctionName=lambda_name, Payload=b'{"echo":"echo"}')
            result_data = result['Payload'].read()
            self.assertEqual(result['StatusCode'], 200)
            self.assertIn('echo', to_str(result_data))
            
            testutil.delete_lambda_function(lambda_name)
    def test_sns_event(self):
        result = self.lambda_client.invoke(
            FunctionName=TEST_LAMBDA_NAME_JAVA, InvocationType='Event',
            Payload=b'{"Records": [{"Sns": {"Message": "{}"}}]}')