HTTP Client Attributes

[Cantor, Scott]

> It is 'none', if one is using the default internally-constructed HttpClient.
> Because of the 1) memory requirements of in-memory and 2) disk
> requirements of disk, we didn't want to make assumptions about either of
> those defaults being ok.

And because they do their own caching, I believe. I think there was internal logic already to remember a cache tag and use it, just not across restarts (whereas the SP actually stores the cache tags on disk, I think). We didn't need the HttpClient's support for the batch case.

-- Scott