Fix crash when the worker is timed-out waiting for master (#874)

Public/Src/Engine/Dll/Distribution/WorkerService.cs

@@ -283,6 +283,7 @@ namespace BuildXL.Engine.Distribution
                 if ((TimestampUtilities.Timestamp - m_lastHeartbeatTimestamp) > EngineEnvironmentSettings.WorkerAttachTimeout)
                 {
                     Exit(failure: "Timed out waiting for attach request from master", isUnexpected: true);
+                    Logger.Log.DistributionWorkerTimeoutFailure(m_appLoggingContext);
                     return false;
                 }
             }

Public/Src/Engine/Dll/Tracing/Log.cs

@@ -726,6 +726,15 @@ namespace BuildXL.Engine.Tracing
             Message = "Failing build on worker due to failure: {failure}")]
         public abstract void DistributionWorkerExitFailure(LoggingContext context, string failure);
 
+        [GeneratedEvent(
+            (ushort)LogEventId.DistributionWorkerTimeoutFailure,
+            EventGenerators = EventGenerators.LocalOnly,
+            EventLevel = Level.Error,
+            Keywords = (int)(Keywords.UserMessage | Keywords.UserError),
+            EventTask = (ushort)Tasks.Distribution,
+            Message = "Timed out waiting for attach request from master")]
+        public abstract void DistributionWorkerTimeoutFailure(LoggingContext context);
+
         [GeneratedEvent(
             (ushort)LogEventId.DistributionTryMaterializeInputsFailedRetry,
             EventGenerators = EventGenerators.LocalOnly,

Public/Src/Engine/Dll/Tracing/LogEventId.cs

@@ -175,7 +175,7 @@ namespace BuildXL.Engine.Tracing
         DistributionWorkerStatus = 7038,
 
         DistributionExecutePipFailedNetworkFailureWarning = 7039,
-        // UNUSED 7040
+        DistributionWorkerTimeoutFailure = 7040,
 
         DistributionBondCall = 7041,
         DistributionDebugMessage = 7042,