Additional sugar: Timer.recordInterval(since: DispatchTime, now: DispatchTime = .now())

[ktoso]

Noticed during our work on apple/swift-cluster-membership#70 and other projects this pattern:

extension Timer {
    /// Records time interval between the passed in `since` dispatch time and `now`.
    func recordInterval(since: DispatchTime, now: DispatchTime = .now()) {
        self.recordNanoseconds(now.uptimeNanoseconds - since.uptimeNanoseconds)
    }
}

emerges a lot when a message contains "sent at" or something like that, and then reporting metrics becomes timer.recordInterval(since: message.sentAt) leaving the user without any having to dance around math with the time amounts

[ktoso]

Yeah this is showing up a lot actually, also here:

).recordNanoseconds(DispatchTime.now().uptimeNanoseconds - request.startTime.uptimeNanoseconds)

https://github.com/slashmo/swift-tracing-examples/pull/2/files and also heard some feedback from community AFAIR.