Ensure calls to Agent.Tracer use null propagation to access child objects (#59)

Author: codebrain

src/Elastic.Apm.NLog/ApmTraceIdLayoutRenderer.cs

@@ -17,8 +17,8 @@ public class ApmTraceIdLayoutRenderer : LayoutRenderer
 
 		protected override void Append(StringBuilder builder, LogEventInfo logEvent)
 		{
-			if (!Agent.IsConfigured || Agent.Tracer?.CurrentTransaction == null)
-				return;
+			if (!Agent.IsConfigured) return;
+			if (Agent.Tracer?.CurrentTransaction == null) return;
 
 			builder.Append(Agent.Tracer.CurrentTransaction.TraceId);
 		}

src/Elastic.Apm.NLog/ApmTransactionIdLayoutRenderer.cs

@@ -17,8 +17,8 @@ public class ApmTransactionIdLayoutRenderer : LayoutRenderer
 
 		protected override void Append(StringBuilder builder, LogEventInfo logEvent)
 		{
-			if (!Agent.IsConfigured || Agent.Tracer?.CurrentTransaction == null)
-				return;
+			if (!Agent.IsConfigured) return;
+			if (Agent.Tracer?.CurrentTransaction == null) return;
 
 			builder.Append(Agent.Tracer.CurrentTransaction.Id);
 		}

src/Elastic.Apm.SerilogEnricher/ElasticApmEnricher.cs

@@ -15,8 +15,8 @@ public sealed class ElasticApmEnricher : ILogEventEnricher
 	{
 		public void Enrich(LogEvent logEvent, ILogEventPropertyFactory propertyFactory)
 		{
-			if (!Agent.IsConfigured || Agent.Tracer.CurrentTransaction == null)
-				return;
+			if (!Agent.IsConfigured) return;
+			if (Agent.Tracer?.CurrentTransaction == null) return;
 
 			logEvent.AddPropertyIfAbsent(propertyFactory.CreateProperty(
 				"ElasticApmTransactionId", Agent.Tracer.CurrentTransaction.Id));