Merge branch 'master' into muzahid/FSSDK-11374

* master:
  [FSSDK-11373] add holdout support and refactor decision logic in DefaultDecisionService (#587)

# Conflicts:
#	OptimizelySwiftSDK.xcodeproj/project.pbxproj
#	Sources/Implementation/DefaultDecisionService.swift
#	Sources/Protocols/OPTBucketer.swift
#	Tests/OptimizelyTests-DataModel/HoldoutTests.swift

Author: muzahidul-opti

Sources/Implementation/DefaultDecisionService.swift

@@ -431,11 +431,12 @@ class DefaultDecisionService: OPTDecisionService {
             logger.i(info)
 
             // bucket user into holdout variation
-            let decisionResponse = bucketer.bucketToVariation(experiment: holdout, bucketingId: bucketingId)
-            
-            reasons.merge(decisionResponse.reasons)
+            let decisionResponse = (bucketer as? DefaultBucketer)?.bucketToVariation(experiment: holdout, bucketingId: bucketingId)
+            if let reason = decisionResponse?.reasons {
+                reasons.merge(reason)
+            }
 
-            bucketedVariation = decisionResponse.result
+            bucketedVariation = decisionResponse?.result
 
             if let variation = bucketedVariation {
                 let info = LogMessage.userBucketedIntoVariationInHoldout(userId, holdout.key, variation.key)

Sources/Protocols/OPTBucketer.swift

@@ -37,15 +37,6 @@ protocol OPTBucketer {
                           experiment: Experiment,
                           bucketingId: String) -> DecisionResponse<Variation>
 
-    /**
-     Bucket a bucketingId into an experiment.
-     - Parameter experiment: The rule in which to bucket the bucketingId.
-     - Parameter bucketingId: The ID to bucket. This must be a non-null, non-empty string.
-     - Returns: The variation the bucketingId was bucketed into.
-     */
-    func bucketToVariation(experiment: ExperimentCore,
-                           bucketingId: String) -> DecisionResponse<Variation>
-
     /**
      Hash the bucketing ID and map it to the range [0, 10000).
      - Parameter bucketingId: The ID for which to generate the hash and bucket values.