In [this PR](https://github.com/localstack/localstack/pull/1200/files) we introduced a new way of starting S3 in a separate process.

In the meantime, the service startup has been significantly reworked, and it seems that we can integrate the S3 starter into the [`multiserver.py`](https://github.com/localstack/localstack/blob/master/localstack/utils/server/multiserver.py) based loading approach that loads multiple APIs in a single process, for performance reasons. We should look into that.
bucket_name = 'test-bucket-%s' % short_uid()
        self.s3_client.create_bucket(Bucket=bucket_name)
        data = '000000000000000000000000000000'
        
        upload_file_object = BytesIO()
        with gzip.GzipFile(fileobj=upload_file_object, mode='w') as filestream:
            filestream.write(data.encode('utf-8'))
        
        self.s3_client.put_object(Bucket=bucket_name, Key='test.gz',
            ContentEncoding='gzip', Body=upload_file_object.getvalue())
        
        downloaded_object = self.s3_client.get_object(Bucket=bucket_name, Key='test.gz')
        download_file_object = BytesIO(downloaded_object['Body'].read())
        with gzip.GzipFile(fileobj=download_file_object, mode='rb') as filestream:
            downloaded_data = filestream.read().decode('utf-8')
        self.assertEqual(downloaded_data, data, '{} != {}'.format(downloaded_data, data))
    def test_set_external_hostname(self):