tracker/udp/server/server.go | 5 ++++-

diff --git a/tracker/udp/server/server.go b/tracker/udp/server/server.go
index 2007233f4f0c067e04ff6c755ef56631eb0ea161..9df2fc67caee6909adbd472a50f15499d1568102 100644
--- a/tracker/udp/server/server.go
+++ b/tracker/udp/server/server.go
@@ -15,7 +15,9 @@ 	"github.com/anacrolix/generics"
 	"github.com/anacrolix/log"
 	trackerServer "github.com/anacrolix/torrent/tracker/server"
 	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/trace"
 
 	"github.com/anacrolix/torrent/tracker/udp"
 )
@@ -47,7 +49,8 @@ 	family udp.AddrFamily,
 	source RequestSourceAddr,
 	body []byte,
 ) (err error) {
-	ctx, span := tracer.Start(ctx, "Server.HandleRequest")
+	ctx, span := tracer.Start(ctx, "Server.HandleRequest",
+		trace.WithAttributes(attribute.Int("payload.len", len(body))))
 	defer span.End()
 	defer func() {
 		if err != nil {