Define FeatureFlag cases for performance monitoring

Author: mokagio

Experiments/Experiments/FeatureFlag.swift

@@ -81,4 +81,39 @@ public enum FeatureFlag: Int {
     /// Enables signing up for a WP.com account.
     ///
     case wpcomSignup
+
+    // MARK: - Performance Monitoring
+    //
+    // This flags are not transient. That is, they are not here to help us rollout a feature,
+    // but to serve a safety switches to granularly turn off performance monitoring if it looks
+    // like we are consuming too many events.
+
+    /// Whether to enable performance monitoring
+    ///
+    case performanceMonitoring
+
+    /// Whether to enable performance monitoring for Core Data operations.
+    ///
+    /// - Note: The app will ignore this if `performanceMonitoring` is `false`
+    case performanceMonitoringCoreData
+
+    /// Whether to enable performance monitoring for file IO operations.
+    ///
+    /// - Note: The app will ignore this if `performanceMonitoring` is `false`
+    case performanceMonitoringFileIO
+
+    /// Whether to enable performance monitoring for networking operations.
+    ///
+    /// - Note: The app will ignore this if `performanceMonitoring` is `false`
+    case performanceMonitoringNetworking
+
+    /// Whether to enable performance monitoring for user interaction events.
+    ///
+    /// - Note: The app will ignore this if `performanceMonitoring` is `false`
+    case performanceMonitoringUserInteraction
+
+    /// Whether to enable performance monitoring for `UIViewController` life-cycle events.
+    ///
+    /// - Note: The app will ignore this if `performanceMonitoring` is `false`
+    case performanceMonitoringViewController
 }