diff --git a/wire_proto.go b/wire_proto.go
index 7f1b41c..4f8d3ea 100644
--- a/wire_proto.go
+++ b/wire_proto.go
@@ -4,6 +4,7 @@ import (
 	"encoding/binary"
 	"io"
 	"net"
+	"slices"
 )
 
 var (
@@ -19,6 +20,7 @@ var (
 // atomic, and this function is safe to use across goroutines. Otherwise,
 // writes may be interleaved.
 func WireWrite(buf *net.Buffers, w io.Writer, attrs []Attr) error {
+	*buf = slices.Grow(*buf, len(*buf)+len(attrs)*4)
 	for i := range attrs {
 		key := attrs[i].Key.key
 		if key == "" {