IPP> NOT - Clients shouldn't use persistent connections for more than 2 connections to the same server

[Hastings, Tom N]

This practical considerations holds for any IPP operations, not just
Get-Notifications.  However, it is particularly important for IPPGET, since
a client is likely to use persistent HTTP connections for a polled
Get-Notifications and MUST use persistent HTTP persistent connections for
Event Wait Mode Get-Notifications.

RFC 2616 "Hypertext Transfer Protocol -- HTTP/1.1" says:

    8.1 Persistent Connections

    8.1.4 Practical Considerations

       Clients that use persistent connections SHOULD limit the number of
       simultaneous connections that they maintain to a given server. A
       single-user client SHOULD NOT maintain more than 2 connections with
       any server or proxy.

We may want to add some sort of reference to the HTTP standard about
persistent connections in the IPPGET Transport and Encoding section, OK?

Tom