tree eb40e43d78c6eeccf6eeae633ecdba44d296fa07
parent 9fceb114c3e8742a53fef55a9c8d0ecc89056305
author Ian Cottrell <iancottrell@google.com> 1584367317 -0400
committer Ian Cottrell <iancottrell@google.com> 1584537721 +0000

internal/telemetry: allow ProcessEvent to modify the event

This allows early exporters to adjust the event for later ones.
This is used to lookup key values from the context if needed.
Also add a Query type event which is intended to perform all event
modifications but nothing else, and is used to lookup values from
the context. This cleans up a weirdness where the current lookup
presumes there will be an exporter with a matching mechanism.

Change-Id: I835d1e0b2511553c30f94b7becfe7b7b5462c111
Reviewed-on: https://go-review.googlesource.com/c/tools/+/223657
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>