Adding metric on iteration start for enabling reproducibility in editor from USim iterations

com.unity.perception/Runtime/Randomization/Scenarios/ScenarioBase.cs

     {
         static ScenarioBase s_ActiveScenario;
 
+        const string k_ScenarioIterationMetricDefinitionId = "DB1B258E-D1D0-41B6-8751-16F601A2E230";
+
+        MetricDefinition m_IterationMetricDefinition;
 
         IEnumerable<Randomizer> activeRandomizers
         {
             // Don't skip the first frame if executing on Unity Simulation
             if (Configuration.Instance.IsSimulationRunningInCloud())
                 m_SkipFrame = false;
+
+            m_IterationMetricDefinition = DatasetCapture.RegisterMetricDefinition("scenario_iteration", "Iteration information for dataset sequences",
+                Guid.Parse(k_ScenarioIterationMetricDefinitionId));
         }
 
         void OnEnable()
         void Start()
         {
             Deserialize();
+        }
+
+        struct IterationMetricData
+        {
+            public int iteration;
         }
 
         void Update()
             if (currentIterationFrame == 0)
             {
                 DatasetCapture.StartNewSequence();
+
+                DatasetCapture.ReportMetric(m_IterationMetricDefinition, new[]
+                {
+                    new IterationMetricData()
+                    {
+                        iteration = currentIteration
+                    }
+                });
                 IterateParameterStates();
                 foreach (var randomizer in activeRandomizers)
                     randomizer.IterationStart();