Classify QUIC stream saturation

agents/rap-node-agent/internal/mesh/fabric_quic_transport.go

@@ -18,6 +18,13 @@ import (
 const fabricQUICNextProto = "rap-fabric-data-session-v1"
 const defaultQUICFabricConnIdleTTL = 5 * time.Minute
 const defaultQUICFabricMaxStreamsPerConn = 64
+const ErrQUICFabricStreamLimitReached = quicFabricError("quic fabric stream limit reached")
+
+type quicFabricError string
+
+func (e quicFabricError) Error() string {
+	return string(e)
+}
 
 type QUICFabricTransport struct {
 	Config            *quic.Config
@@ -231,7 +238,7 @@ func (t *QUICFabricTransport) reserveStream(key string, conn *quic.Conn) error {
 	}
 	if entry.activeStreams >= limit {
 		t.stats.StreamLimitRejects++
-		return fmt.Errorf("quic fabric stream limit reached")
+		return ErrQUICFabricStreamLimitReached
 	}
 	entry.activeStreams++
 	entry.lastUsed = time.Now()