Plack::middleware::deflater is a middleware to encode your response body in gzip or deflate, based on the accept-encoding http request header. while saving a little bandwidth it will increase the plack server load, so ideally you should handle this on the frontend reverse proxy servers.

this middleware removes content-length and streams encoded content, which means the server should support http/1.1 chunked response or downgrade to http/1.0 and close the connection.