Fix nullability warnings

Author: tbdrake

Serilog.Sinks.Network.Test/JsonFormatter.cs

@@ -17,7 +17,7 @@ public class JsonFormatter
     {
         private static LoggerAndSocket ConfigureTestLogger(
             ITextFormatter? formatter = null,
-            ILogEventEnricher[] enrichers = null
+            ILogEventEnricher[]? enrichers = null
         )
         {
             var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
@@ -79,7 +79,7 @@ public async Task IncludesCurrentActivityTraceAndSpanIds()
 
             var receivedData = await ServerPoller.PollForReceivedData(fixture.Socket);
 
-            receivedData.Should().Contain($"\"traceId\":\"{activity.TraceId}\"");
+            receivedData.Should().Contain($"\"traceId\":\"{activity!.TraceId}\"");
             receivedData.Should().Contain($"\"spanId\":\"{activity.SpanId}\"");
         }
 
@@ -119,7 +119,7 @@ public async Task WritesTraceAndSpanIdsBeforeDuplicatePropertiesFromEnrichers()
 
             var receivedData = await ServerPoller.PollForReceivedData(fixture.Socket);
 
-            var indexOfTraceId = receivedData.IndexOf($"\"traceId\":\"{activity.TraceId}\"");
+            var indexOfTraceId = receivedData.IndexOf($"\"traceId\":\"{activity!.TraceId}\"");
             var indexOfTraceIdFromEnricher = receivedData.IndexOf("\"traceId\":\"traceId-from-enricher\"");
             indexOfTraceId.Should().BePositive().And.BeLessThan(indexOfTraceIdFromEnricher);
 
@@ -139,4 +139,4 @@ private static ActivityListener CreateAndAddActivityListener(string sourceName)
             return activityListener;
         }
     }
-}
+}