This change adds a cache of undelivered diagnostics on the server-side.
If we fail to send a diagnostic once, we will retry the next time that
the server sends diagnostics.
Change-Id: I161dfad8ea1d2cfdcee933baed2d6872dc03b0c0
Reviewed-on: https://go-review.googlesource.com/c/tools/+/167737
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>