buffet: Push state changed to the server immediately

Current delay for polling_period_ms is not acceptable. We'd like to
see state change on server immediately.
Simple throttling to 1 update per seconds.

BUG=brillo:1124
TEST=`FEATURES=test emerge-gizmo buffet`

Change-Id: Id042e1a6445850d024849e689b8d305c5c3af30f
Reviewed-on: https://chromium-review.googlesource.com/273367
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
Trybot-Ready: Vitaly Buka <vitalybuka@chromium.org>
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
2 files changed
tree: 1833290811fb0b2ff05b624802a6ef585a8c74fb
  1. buffet/