Initial release

Sources/KnotchyCore/Stream/ContentReadiness.swift

@@ -0,0 +1,39 @@
+/// Decides when Starting ends. Frames and progress before NAVIGATED come from the agent's
+/// about:blank bootstrap and never count; `afterHello` is a backstop if NAVIGATED never arrives.
+public struct ContentReadiness: Sendable {
+    public static let afterNavigated: Duration = .seconds(15)
+    public static let afterHello: Duration = .seconds(25)
+
+    public private(set) var isReady = false
+    private var helloAt: ContinuousClock.Instant?
+    private var navigatedAt: ContinuousClock.Instant?
+
+    public init() {}
+
+    public mutating func hello(at now: ContinuousClock.Instant) {
+        if helloAt == nil { helloAt = now }
+    }
+
+    public mutating func navigated(at now: ContinuousClock.Instant) {
+        if navigatedAt == nil { navigatedAt = now }
+    }
+
+    public mutating func frame(isUniform: Bool) {
+        if navigatedAt != nil, !isUniform { isReady = true }
+    }
+
+    public mutating func progress(_ percent: Int) {
+        if navigatedAt != nil, percent >= 100 { isReady = true }
+    }
+
+    public mutating func tick(now: ContinuousClock.Instant) {
+        if let deadline = nextDeadline, now >= deadline { isReady = true }
+    }
+
+    public var nextDeadline: ContinuousClock.Instant? {
+        guard !isReady else { return nil }
+        return [navigatedAt.map { $0 + Self.afterNavigated }, helloAt.map { $0 + Self.afterHello }]
+            .compactMap { $0 }
+            .min()
+    }
+}