NSURLConnection returns 200 when the connection is closed

Not what I was expecting! Let me show you; here's a testserver.go to hijack and close the connection:

package main

import (
    "net/http"
)

func handler(w http.ResponseWriter, r *http.Request) {
}

func main() {
    http.HandleFunc("/", handler)
        http.HandleFunc("/hijack", func(w http.ResponseWriter, r *http.Request) {
        hj, ok := w.(http.Hijacker)
        if !ok {
            http.Error(w, "webserver doesn't support hijacking", http.StatusInternalServerError)
            return
        }
        conn, _, _ := hj.Hijack()
        conn.Close()
    })
    http.ListenAndServe(":8080", nil)
}

Here's what it looks like via curl (after running "go run testserver.go")

~  ᐅ curl -v http://localhost:8080/hijack
* About to connect() to localhost port 8080 (#0)
*   Trying 127.0.0.1...
* connected
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /hijack HTTP/1.1
> User-Agent: curl/7.24.0 (x86_64-apple-darwin12.0) libcurl/7.24.0 OpenSSL/0.9.8r zlib/1.2.5
> Host: localhost:8080
> Accept: */*
> 
* Empty reply from server
* Connection #0 to host localhost left intact
curl: (52) Empty reply from server
* Closing connection #0

Now let's see what NSURLConnection's sendAsynchronousRequest completion handler reports:

[NSURLConnection sendAsynchronousRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://localhost:8080/hijack"]] queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
    NSLog(@"%d", [(NSHTTPURLResponse *)response statusCode]);
    NSLog(@"%@", error);
 }];

--
2013-05-09 14:41:00.221 testserver[59315:c07] 200
2013-05-09 14:41:00.222 testserver[59315:c07] (null)

There you have it! Connection closed results in a 200 http response code and no error!