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`
bucket = 'test-bucket-%s' % short_uid()
        s3_client = aws_stack.connect_to_service('s3')
        s3_client.create_bucket(Bucket=bucket)
        s3_client.put_bucket_cors(
            Bucket=bucket,
            CORSConfiguration={
                'CORSRules': [{'AllowedMethods': ['GET', 'POST', 'PUT', 'DELETE'],
                               'AllowedOrigins': ['localhost']}]
            }
        )
        response = s3_client.get_bucket_cors(Bucket=bucket)
        self.assertEqual(response['ResponseMetadata']['HTTPStatusCode'], 200)
        
        s3_client.delete_bucket(Bucket=bucket)
    def test_s3_uppercase_names(self):
        
        bucket_name = 'TestUpperCase-%s' % short_uid()
        self.s3_client.create_bucket(Bucket=bucket_name)
        
        object_key = 'camelCaseKey'
        self.s3_client.put_object(Bucket=bucket_name, Key=object_key, Body='something')
        self.s3_client.get_object(Bucket=bucket_name, Key=object_key)
        self.assertRaises(Exception, self.s3_client.get_object, Bucket=bucket_name, Key=object_key.lower())
    def test_s3_get_response_headers(self):