fix(killswitches): Always emit a metric if there is a match

[untitaker]

Emitting a metric for every non-matched value is slow. But for the case
where we actually use the killswitch, we should always know how much we
dropped.

[untitaker]

tagging @JoshFerge as IIRC he is the person who added emit_metrics flag.

[JoshFerge]

makes sense, worth just keeping an eye on anything super high volume where we killswitch a lot for perf. regressions but seems unlikely to cause problems!

[untitaker]

@JoshFerge

makes sense, worth just keeping an eye on anything super high volume where we killswitch a lot for perf. regressions but seems unlikely to cause problems!

I'm not aware of anything like that in our own uses of killswitches at least, but that's kind of the reason why i'm tagging you, if you know something like that where we keep a killswitch enabled now would be a good time to speak about it.

[JoshFerge]

@JoshFerge

makes sense, worth just keeping an eye on anything super high volume where we killswitch a lot for perf. regressions but seems unlikely to cause problems!

I'm not aware of anything like that in our own uses of killswitches at least, but that's kind of the reason why i'm tagging you, if you know something like that where we keep a killswitch enabled now would be a good time to speak about it.

i'm not aware either, should be good!