Remove duplicate Content-Length headers that are rejected by Puma 5.6.4.

[nialbima]

Puma's 5.6.4 update prevents Content-Length headers of the form "125, 125" from being accepted by the server. Faye seems to be adding them in a number of locations, and removing the code that supported adding additional Content-Length headers to requests made it possible to continue to use our implementation of ServeryProxy to run integration tests against a simulated Faye backend running in Puma. Because rack_adapter_spec explicitly checks for the presence of Content-Length headers, this seems to resolve the bug.

[jcoglan]

Could you explain further how you're observing headers of the form 125, 125? When I run the example server with Puma 5.6.4, it returns a well-formed content-length header:

$ curl -si http://localhost:7000/bayeux -H 'content-type: application/json' -d '{ "channel": "/meta/handshake", "supportedConnectionTypes": ["long-polling"], "version": "1.0" }'
HTTP/1.1 200 OK
Content-Type: application/json; charset=utf-8
Cache-Control: no-cache, no-store
X-Content-Type-Options: nosniff
Content-Length: 300

[{"channel":"/meta/handshake","successful":true,"version":"1.0","supportedConnectionTypes":["long-polling","cross-origin-long-polling","callback-polling","websocket","eventsource","in-process"],"clientId":"kia6okj2m84lhodxy7fdm2nk7deo2df","advice":{"reconnect":"retry","interval":0,"timeout":25000}}]

None of the points in the code where you've introduced changes should be producing headers like 125, 125, because they all stringify a single number that we got from String#bytesize.

[jcoglan]

On the commit you're asking to pull from, the server doesn't return a content-length header at all, which is incorrect:

$ curl -si http://localhost:7000/bayeux -H 'content-type: application/json' -d '{ "channel": "/meta/handshake", "supportedConnectionTypes": ["long-polling"], "version": "1.0" }'
HTTP/1.1 200 OK
Content-Type: application/json; charset=utf-8
Cache-Control: no-cache, no-store
X-Content-Type-Options: nosniff

[{"channel":"/meta/handshake","successful":true,"version":"1.0","supportedConnectionTypes":["long-polling","cross-origin-long-polling","callback-polling","websocket","eventsource","in-process"],"clientId":"ncpmyfdtv7wz9gc7zm9yw2gnl55ar7o","advice":{"reconnect":"retry","interval":0,"timeout":25000}}]