sqs.changeMessageVisibility according to [this](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_ChangeMessageVisibility.html#API_ChangeMessageVisibility_Examples) makes a request directly to the Queue's URL rather than via the SQS Endpoint. (I'm already setting SQS endpoint to LOCALSTACK_HOSTNAME - makes no difference for this call)..

In localstack the queue URL host returned is by default set to the value of HOSTNAME_EXTERNAL, which I'm setting to localstack, but calling this method within a lambda, does not work and I get the error:

```
UnknownEndpoint: Inaccessible host: `localstack'. This service may not be available in the `us-east-1' region. 
```

So, how can I make the queue URL accessible from within a lambda using localstack? Effectively I need to make **http://localstack** accessible from within lambda.

I'm using the following cmd to start localstack:

```
LAMBDA_EXECUTOR=docker-reuse DEBUG=1 LAMBDA_REMOTE_DOCKER=0 DATA_DIR=/tmp/localstack/data HOSTNAME_EXTERNAL=localstack localstack start
```
backend_url,
            path=self.API_PATH_HTTP_BACKEND
        )
        url = self.gateway_request_url(
            api_id=result['id'],
            stage_name=self.TEST_STAGE_NAME,
            path=self.API_PATH_HTTP_BACKEND
        )
        
        origin = 'localhost'
        result = requests.options(url, headers={'origin': origin})
        self.assertEqual(result.status_code, 200)
        self.assertTrue(re.match(result.headers['Access-Control-Allow-Origin'].replace('*', '.*'), origin))
        self.assertIn('POST', result.headers['Access-Control-Allow-Methods'])
        
        result = requests.get(url)
        self.assertEqual(result.status_code, 200)
        self.assertEqual(json.loads(to_str(result.content))['data'], '{}')
        
        data = json.dumps({'data': 123})
        result = requests.post(url, data=data)
        self.assertEqual(result.status_code, 200)
        self.assertEqual(json.loads(to_str(result.content))['data'], data)
        
        data = 'test=123'
        ctype = 'application/x-www-form-urlencoded'
        result = requests.post(url, data=data, headers={'content-type': ctype})
        self.assertEqual(result.status_code, 200)
        content = json.loads(to_str(result.content))
        headers = CaseInsensitiveDict(content['headers'])