when I try to upload a large file, localstack basically freezes (and eventually times out).  
But if the file is all `1` bytes it succeeds.

succeeds:
```bash
aws s3 --endpoint-url=http://localhost:4572 mb s3://testbucket
python -c "print '\x01'*10000000" > testfile
echo $(ls -ahl | grep testfile)
aws s3 --endpoint-url=http://localhost:4572 cp testfile s3://testbucket/testfile
```

fails:
```bash
aws s3 --endpoint-url=http://localhost:4572 mb s3://testbucket
python -c "print 'a'*10000000" > testfile
echo $(ls -ahl | grep testfile)
aws s3 --endpoint-url=http://localhost:4572 cp testfile s3://testbucket/testfile
```
so, for me, both the file content and its size determine if this triggers or not. 
I'm using the latest version `0.9.5`
queue_url = self.sqs_client.create_queue(QueueName=TEST_QUEUE_FOR_BUCKET_WITH_NOTIFICATION)['QueueUrl']
        queue_attributes = self.sqs_client.get_queue_attributes(QueueUrl=queue_url, AttributeNames=['QueueArn'])
        return queue_url, queue_attributes
    def _create_test_notification_bucket(self, queue_attributes):
        self.s3_client.create_bucket(Bucket=TEST_BUCKET_WITH_NOTIFICATION)
        self.s3_client.put_bucket_notification_configuration(
            Bucket=TEST_BUCKET_WITH_NOTIFICATION,
            NotificationConfiguration={
                'QueueConfigurations': [
                    {
                        'QueueArn': queue_attributes['Attributes']['QueueArn'],
                        'Events': ['s3:ObjectCreated:*']
                    }
                ]
            }
        )
    def _get_test_queue_message_count(self, queue_url):
        queue_attributes = self.sqs_client.get_queue_attributes(
            QueueUrl=queue_url, AttributeNames=['ApproximateNumberOfMessages']
        )
        return queue_attributes['Attributes']['ApproximateNumberOfMessages']
    def _delete_bucket(self, bucket_name, keys=[]):