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.
cls.test_java_jar = load_file(TEST_LAMBDA_JAVA, mode='rb')
        cls.test_java_zip = testutil.create_zip_file(TEST_LAMBDA_JAVA, get_content=True)
        testutil.create_lambda_function(
            func_name=TEST_LAMBDA_NAME_JAVA,
            zip_file=cls.test_java_jar,
            runtime=LAMBDA_RUNTIME_JAVA8,
            handler='cloud.localstack.sample.LambdaHandler'
        )
        
        testutil.create_lambda_function(
            func_name=TEST_LAMBDA_NAME_JAVA_STREAM,
            zip_file=cls.test_java_jar,
            runtime=LAMBDA_RUNTIME_JAVA8,
            handler='cloud.localstack.sample.LambdaStreamHandler'
        )
        
        testutil.create_lambda_function(
            func_name=TEST_LAMBDA_NAME_JAVA_SERIALIZABLE,
            zip_file=cls.test_java_zip,
            runtime=LAMBDA_RUNTIME_JAVA8,
            handler='cloud.localstack.sample.SerializedInputLambdaHandler'
        )
    @classmethod
    def tearDownClass(cls):
        
        testutil.delete_lambda_function(TEST_LAMBDA_NAME_JAVA)
        testutil.delete_lambda_function(TEST_LAMBDA_NAME_JAVA_STREAM)
        testutil.delete_lambda_function(TEST_LAMBDA_NAME_JAVA_SERIALIZABLE)
    def test_java_runtime(self):
        self.assertIsNotNone(self.test_java_jar)