_2016-02-06_

 *  New: WebSockets now defer some writes. This should improve performance for
    some applications.
 *  New: Override `equals()` and `hashCode()` in our new cookie class. This
    class now defines equality by value rather than by reference.
 *  New: Handle 408 responses by retrying the request. This allows servers to
    direct clients to retry rather than failing permanently.