The .NET 4.5 C# client leaks connections given responses with non-successful status code

[halter73]

Expected behavior

When a request made by the .NET 4.5 SignalR client fails due to a non-successful status code, the underlying connection should be gracefully closed by the time the SignalR client enters the disconnected state.

Actual behavior

The underlying connection stays open because response was never disposed prior to throwing here and here. This can lead to a large number of open connections in combination with manual reconnect logic.

Steps to reproduce

Repeatedly attempt to connect (i.e manual reconnect logic) to a SignalR endpoint that responds with a 401 from the /negotiate.

@davidfowl