[FSSDK-11371] parsing holdout section from the datafile

Sources/Data Model/Experiment.swift

@@ -16,7 +16,7 @@
 
 import Foundation
 
-struct Experiment: Codable, OptimizelyExperiment, ExperimentCore {
+struct Experiment: Codable, ExperimentCore {
     enum Status: String, Codable {
         case running = "Running"
         case launched = "Launched"

Sources/Data Model/Holdout.swift

@@ -32,15 +32,32 @@ struct Holdout: Codable, ExperimentCore {
     var trafficAllocation: [TrafficAllocation]
     var audienceIds: [String]
     var audienceConditions: ConditionHolder?
-    var includedFlags: [String]?
-    var excludedFlags: [String]?
+    var includedFlags: [String]
+    var excludedFlags: [String]
 
     enum CodingKeys: String, CodingKey {
         case id, key, status, layerId, variations, trafficAllocation, audienceIds, audienceConditions, includedFlags, excludedFlags
     }
 
     // replace with serialized string representation with audience names when ProjectConfig is ready
     var audiences: String = ""
+
+
+    init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+
+        id = try container.decode(String.self, forKey: .id)
+        key = try container.decode(String.self, forKey: .key)
+        status = try container.decode(Status.self, forKey: .status)
+        layerId = try container.decode(String.self, forKey: .layerId)
+        variations = try container.decode([Variation].self, forKey: .variations)
+        trafficAllocation = try container.decode([TrafficAllocation].self, forKey: .trafficAllocation)
+        audienceIds = try container.decode([String].self, forKey: .audienceIds)
+        audienceConditions = try container.decodeIfPresent(ConditionHolder.self, forKey: .audienceConditions)
+
+        includedFlags = try container.decodeIfPresent([String].self, forKey: .includedFlags) ?? []
+        excludedFlags = try container.decodeIfPresent([String].self, forKey: .excludedFlags) ?? []
+    }
 }
 
 extension Holdout: Equatable {

Sources/Optimizely/OptimizelyConfig.swift

@@ -42,6 +42,9 @@ public protocol OptimizelyExperiment {
     var variationsMap: [String: OptimizelyVariation] { get }
 }
 
+// Experiment compliances OptimizelyExperiment
+extension Experiment: OptimizelyExperiment { }
+
 public protocol OptimizelyFeature {
     var id: String { get }
     var key: String { get }