Don't emit a msg if there is none to emit

text_formatter.go

diff --git a/text_formatter.go b/text_formatter.go
index 17cc298..06ef202 100644
--- a/text_formatter.go
+++ b/text_formatter.go
@@ -84,7 +84,9 @@
 			f.appendKeyValue(b, "time", entry.Time.Format(timestampFormat))
 		}
 		f.appendKeyValue(b, "level", entry.Level.String())
-		f.appendKeyValue(b, "msg", entry.Message)
+		if entry.Message != "" {
+			f.appendKeyValue(b, "msg", entry.Message)
+		}
 		for _, key := range keys {
 			f.appendKeyValue(b, key, entry.Data[key])
 		}