Loving this tool so far! I recently ran into an issue where it seems that performing a Put or a Get operation against my local S3 bucket is collapsing XML-like structures. This in turn causes MD5 digest validation errors.

I have an S3 bucket...
```
aws --endpoint-url=http://localhost:4572 s3api create-bucket --bucket my-bucket
```

I start with a file called **test.xml**:
```
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl"?>
<submission>
    <field1>fwefwefewfew</field1>
    <field2>fwefwefwe</field2>
    <field3>fefwefwe</field3>
</submission>
```

I then put this object into S3 using the following command:
```
 aws --endpoint-url=http://localhost:4572 s3api put-object --bucket my-bucket --key data/test1 --body test.xml
```

I'll grab the file back using the following command:
```
aws --endpoint-url=http://localhost:4572 s3api get-object --bucket my-bucket --key data/test1 test-back.xml
```

The file now looks like this:
```
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl"?>
<submission><field1>fwefwefewfew</field1><field2>fwefwefwe</field2><field3>fefwefwe</field3></submission>
```

I found this while troubleshooting the following exception stack:
```
com.amazonaws.SdkClientException: Unable to verify integrity of data download.  Client calculated content hash didn't match hash calculated by Amazon S3.  The data may be corrupt.
	at com.amazonaws.services.s3.internal.DigestValidationInputStream.validateMD5Digest(DigestValidationInputStream.java:79)
	at com.amazonaws.services.s3.internal.DigestValidationInputStream.read(DigestValidationInputStream.java:61)
	at com.amazonaws.internal.SdkFilterInputStream.read(SdkFilterInputStream.java:72)
	at java.io.FilterInputStream.read(FilterInputStream.java:107)
	at com.amazonaws.util.IOUtils.toByteArray(IOUtils.java:44)
	at com.amazonaws.util.IOUtils.toString(IOUtils.java:58)
	at com.amazonaws.services.s3.AmazonS3Client.getObjectAsString(AmazonS3Client.java:1485)
```

I was able to work around this bug when I collapsed the XML structure myself prior to adding the file to S3. This is not ideal though.

Any ideas on why this is happening? I am using localstack version 0.8.8, installed with pip.

Thanks for any help!

'responseElements': {
                'x-amz-request-id': short_uid(),
                'x-amz-id-2': 'eftixk72aD6Ap51TnqcoF8eFidJG9Z/2'  
            },
            's3': {
                's3SchemaVersion': '1.0',
                'configurationId': 'testConfigRule',
                'bucket': {
                    'name': bucket_name,
                    'ownerIdentity': {
                        'principalId': 'A3NL1KOZZKExample'
                    },
                    'arn': 'arn:aws:s3:::%s' % bucket_name
                },
                'object': {
                    'key': file_name,
                    'size': file_size,
                    'eTag': 'd41d8cd98f00b204e9800998ecf8427e',
                    'versionId': version_id,
                    'sequencer': '0055AED6DCD90281E5'
                }
            }
        }]
    }
def queue_url_for_arn(queue_arn):
    sqs_client = aws_stack.connect_to_service('sqs')
    parts = queue_arn.split(':')
    return sqs_client.get_queue_url(QueueName=parts[5],
        QueueOwnerAWSAccountId=parts[4])['QueueUrl']
def send_notifications(method, bucket_name, object_path, version_id):