Unable to update/remove session data if no response content

[shirozatou]

This is due to BeforeSend hook is not called when

1. No response content
2. Scoped plugin

Sample

    routing {
        route("test") {
            install(Sessions) { // not global
                cookie<String>(name = "token")
            }
            post("clear") {
                call.sessions.clear("token")
                if (call.request.queryParameters["c"] == "1") { // flag to set empty content
                    call.respond("")
                }
                call.response.status(HttpStatusCode.OK) // or HttpStatusCode.NoContent
            }
        }
    }

curl

> POST /test/clear?c=1 HTTP/1.1
> Host: 127.0.0.1:8080
> Accept: */*
> Cookie: token=foo
> 
< HTTP/1.1 200 OK
< Set-Cookie: token=; Max-Age=0; Expires=Thu, 01 Jan 1970 00:00:00 GMT; Path=/; HttpOnly; $x-enc=URI_ENCODING
< Content-Length: 0
< Content-Type: text/plain; charset=UTF-8
< 

> POST /test/clear HTTP/1.1
> Host: 127.0.0.1:8080
> Accept: */*
> Cookie: token=foo
> 
< HTTP/1.1 200 OK
< Content-Length: 0
<