[analytics] initial sendReport API

[pq]

A jumping off point for a sendReport implementation.

Next step is to add params and do some experimenting w/ DTD.

You'll note that this handles error conditions a little differently than the other DTD interactions and I'm open to feedback. (In those cases we return futures that will blow up if interrogated. I'm not sure we want to do that here (or even if we'll ever ask?)) Dunno.

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[pq]

/gemini