Expose NetworkStream+Send to the server

[lightningdev45]

I need access to the downcast methods on NetworkStream+Send on the server in order to gain access to a TcpStream object. This will allow me to implement an iron middleware to upgrade connections to websocket connections, following the work already done in rust-websockets.

Iron currently only has access to a NetworkStream which is obtained by calling "deconstruct" on the request object provided by hyper.

[seanmonstar]

The changes to do here is to change the &'a NetworkStream in hyper::server::Request to be &'a (NetworkStream + Send).

[reem]

Alternatively just add downcasting to NetworkStream proper, in addition to the impl for NetworkStream + Send.

[seanmonstar]

Ah yes, we could duplicate the definition for impl NetworkStream (grumble grumble)...

[lightningdev45]

I'm going to attempt to make the changes myself using the first proposed solution. If I get stuck I'll post on this thread. When I'm ready I'll make a PR

[seanmonstar]

The second one would be easier. The first would be preferred if there's a need to send that trait object to another thread...

[lightningdev45]

Wouldn't that be useful? For instance, I initialize a websocket connection. Later on, my client makes an http request and that request wants to be able to send data through the websocket while the new request is still processing. I'm just not sure if this scenario would require passing NetworkStream+Send to more than one thread(my intuition tells me it would). In any case I will attempt both