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
```
queue_name = 'queue-%s' % short_uid()
        queue_info = self.client.create_queue(QueueName=queue_name)
        queue_url = queue_info['QueueUrl']
        self.assertIn(queue_name, queue_url)
        
        self.client.send_message(QueueUrl=queue_url, MessageBody='msg123')
        for i in range(2):
            messages = self.client.receive_message(QueueUrl=queue_url, VisibilityTimeout=0)['Messages']
            self.assertEqual(len(messages), 1)
            self.assertEqual(messages[0]['Body'], 'msg123')
        
        self.client.delete_message(QueueUrl=queue_url, ReceiptHandle=messages[0]['ReceiptHandle'])
        response = self.client.receive_message(QueueUrl=queue_url)
        self.assertFalse(response.get('Messages'))
        
        self.client.send_message(QueueUrl=queue_url, MessageBody='msg234')
        messages = self.client.receive_message(QueueUrl=queue_url)['Messages']
        response = self.client.receive_message(QueueUrl=queue_url)
        self.assertFalse(response.get('Messages'))
        self.client.change_message_visibility(QueueUrl=queue_url,
                                              ReceiptHandle=messages[0]['ReceiptHandle'], VisibilityTimeout=0)
        for i in range(2):
            messages = self.client.receive_message(QueueUrl=queue_url, VisibilityTimeout=0)['Messages']
            self.assertEquals(len(messages), 1)
            self.assertEquals(messages[0]['Body'], 'msg234')
        
        self.client.delete_queue(QueueUrl=queue_url)
    def test_create_fifo_queue(self):