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.
resources = {}
        template = self.APIGATEWAY_DATA_INBOUND_TEMPLATE % (kinesis_stream)
        resource_path = self.API_PATH_DATA_INBOUND.replace('/', '')
        resources[resource_path] = [{
            'httpMethod': 'POST',
            'authorizationType': 'NONE',
            'integrations': [{
                'type': 'AWS',
                'uri': 'arn:aws:apigateway:%s:kinesis:action/PutRecords' % config.DEFAULT_REGION,
                'requestTemplates': {
                    'application/json': template
                }
            }]
        }, {
            'httpMethod': 'GET',
            'authorizationType': 'NONE',
            'integrations': [{
                'type': 'AWS',
                'uri': 'arn:aws:apigateway:%s:kinesis:action/ListStreams' % config.DEFAULT_REGION,
                'requestTemplates': {
                    'application/json': '{}'
                }
            }]
        }]
        return aws_stack.create_api_gateway(
            name=gateway_name,
            resources=resources,
            stage_name=self.TEST_STAGE_NAME
        )
    def connect_api_gateway_to_http(self, gateway_name, target_url, methods=[], path=None):