Update SwiftPrometheus to use SwiftMetric 2.* (TimeUnit change to struct) (#31)

* Update SwiftPrometheus to use SwiftMetric 2.* SemVer (TimeUnit def change)

* Update Package.swift

* Update SummaryTests.swift

* Update Summary.swift

Author: tdotclare

Package.resolved

@@ -13,7 +13,7 @@ let package = Package(
             targets: ["PrometheusExample"]),
     ],
     dependencies: [
-        .package(url: "https://github.com/apple/swift-metrics.git", from: "1.2.0"),
+        .package(url: "https://github.com/apple/swift-metrics.git", from: "2.0.0"),
         .package(url: "https://github.com/apple/swift-nio.git", from: "2.0.0"),
     ],
     targets: [

Package.swift

@@ -1,5 +1,5 @@
 import NIOConcurrencyHelpers
-import enum CoreMetrics.TimeUnit
+import struct CoreMetrics.TimeUnit
 import Dispatch
 
 /// Label type Summaries can use
@@ -125,16 +125,10 @@ public class PromSummary<NumType: DoubleRepresentable, Labels: SummaryLabels>: P
         }
     }
 
+    // Updated for SwiftMetrics 2.0 to be unit agnostic if displayUnit is set or default to nanoseconds.
     private func format(_ v: Double) -> Double {
-        guard let displayUnit = self.displayUnit else { return v }
-        switch displayUnit {
-        case .days: return (v / 1_000_000_000) * 60 * 60 * 24
-        case .hours: return (v / 1_000_000_000) * 60 * 60
-        case .minutes: return (v / 1_000_000_000) * 60
-        case .seconds: return v / 1_000_000_000
-        case .milliseconds: return v / 1_000_000
-        case .nanoseconds: return v
-        }
+        let displayUnitScale = self.displayUnit?.scaleFromNanoseconds ?? 1
+        return v / Double(displayUnitScale)
     }
 
     internal func preferDisplayUnit(_ unit: TimeUnit) {

Sources/Prometheus/MetricTypes/Summary.swift

@@ -76,6 +76,7 @@ final class SummaryTests: XCTestCase {
 
         summary.recordSeconds(1)
         summary.recordMilliseconds(2 * 1_000)
+        summary.recordMicroseconds(3 * 1_000_000)
         summary.recordNanoseconds(4 * 1_000_000_000)
         summary.recordSeconds(10000)
 
@@ -91,8 +92,8 @@ final class SummaryTests: XCTestCase {
         my_summary{quantile="0.95"} 10000.0
         my_summary{quantile="0.99"} 10000.0
         my_summary{quantile="0.999"} 10000.0
-        my_summary_count 4
-        my_summary_sum 10007.0
+        my_summary_count 5
+        my_summary_sum 10010.0
         """)
     }