new features

Sources/MonitorCore/NetworkRateTracker.swift

@@ -0,0 +1,22 @@
+import Foundation
+
+/// Rates are computed per container so new or removed containers do not cause
+/// spikes from their lifetime counters. Counter resets contribute zero.
+public struct NetworkRateTracker: Sendable {
+    private struct Counter: Sendable { var date: Date; var rx: Double; var tx: Double }
+    private var counters: [String: Counter] = [:]
+    public init() {}
+    public mutating func sample(_ resources: [Resource], at date: Date) -> (rx: Double, tx: Double) {
+        var next: [String: Counter] = [:], rxRate = 0.0, txRate = 0.0
+        for resource in resources {
+            guard let rx = resource.rxBytes, let tx = resource.txBytes else { continue }
+            if let previous = counters[resource.id] {
+                let seconds = date.timeIntervalSince(previous.date)
+                if seconds > 0 { rxRate += max(0, rx - previous.rx) / seconds; txRate += max(0, tx - previous.tx) / seconds }
+            }
+            next[resource.id] = Counter(date: date, rx: rx, tx: tx)
+        }
+        counters = next
+        return (rxRate, txRate)
+    }
+}