[netstack] check LogCobaltEvents for errors

We missed this back in November:

https://fuchsia-review.googlesource.com/c/fuchsia/+/318745/61/src/connectivity/network/netstack/netstack.go#115

Bug: 55298
Change-Id: If9f83122bcb971ad516cd7a8625dd0a3b20d78a2
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/404903
Commit-Queue: Bert Muthalaly <stijlist@google.com>
Reviewed-by: Ghanan Gowripalan <ghanan@google.com>
Testability-Review: Ghanan Gowripalan <ghanan@google.com>
diff --git a/src/connectivity/network/netstack/netstack.go b/src/connectivity/network/netstack/netstack.go
index acfaf18..9a7eda8 100644
--- a/src/connectivity/network/netstack/netstack.go
+++ b/src/connectivity/network/netstack/netstack.go
@@ -128,7 +128,10 @@
 		case <-ctx.Done():
 			return ctx.Err()
 		case <-ticker.C:
-			cobaltLogger.LogCobaltEvents(context.Background(), c.Collect())
+			events := c.Collect()
+			if status, err := cobaltLogger.LogCobaltEvents(context.Background(), events); err != nil || status != cobalt.StatusOk {
+				syslog.Warnf("cobaltLogger.LogCobaltEvents(_, %+v) = %s, %s", events, status, err)
+			}
 		}
 	}
 }