tree 6df884b1d8e7234472d6bf0d53fba1ae8d5842bb
parent 0325d671925d488bf686e5e445b4b8dd561732cb
author Ian Cottrell <iancottrell@google.com> 1619795314 -0400
committer Ian Cottrell <iancottrell@google.com> 1620877681 +0000

event: changes to support context in start

Start now has a fluent builder, this makes constructing start events conceptually the same as all other types.
It also allows the span builder to carry the context, which is then passed to the handler.
Handler now has a method per kind rather than a single Handle method, and Kind has been removed from event.
This (amongst other things) allows Start to have a different signature so it can take and return a context.
It is also the fastest implementation so far across all benchmarks.
Disabled is now implemented by build tag instead of boolean.

Change-Id: Id00a22633a35bfaccf20ea5fcc1f918f849411fd
Reviewed-on: https://go-review.googlesource.com/c/exp/+/319070
Trust: Ian Cottrell <iancottrell@google.com>
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jonathan Amsterdam <jba@google.com>