make sure that VarIntLen can be inlined

internal/utils/varint.go

@@ -97,5 +97,10 @@ func VarIntLen(i uint64) protocol.ByteCount {
 	if i <= maxVarInt8 {
 		return 8
 	}
-	panic(fmt.Sprintf("%#x doesn't fit into 62 bits", i))
+	// Don't use a fmt.Sprintf here to format the error message.
+	// The function would then exceed the inlining budget.
+	panic(struct {
+		message string
+		num     uint64
+	}{"value doesn't fit into 62 bits: ", i})
 }