this shuffles things so there a single exporter API rather than an observer
It also removes most of the globals.
per telemetry type.
Change-Id: Iaa82abe2ded1fff9df8e067ed4a55bcbd9d9591f
Reviewed-on: https://go-review.googlesource.com/c/tools/+/190405
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
