--- format.go.orig	2022-01-07 15:25:57.762807000 +0100
+++ format.go	2022-01-07 15:26:16.154491000 +0100
@@ -1,8 +1,11 @@
+// Code generated from the Go standard library. DO NOT EDIT
+// GENERATED FILE DO NOT EDIT
+//
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package fmt
+package rfmt
 
 import (
 	"strconv"
@@ -65,25 +68,17 @@
 	if n <= 0 { // No padding bytes needed.
 		return
 	}
-	buf := *f.buf
-	oldLen := len(buf)
-	newLen := oldLen + n
 	// Make enough room for padding.
-	if newLen > cap(buf) {
-		buf = make(buffer, cap(buf)*2+n)
-		copy(buf, *f.buf)
-	}
+	f.buf.Grow(n)
 	// Decide which byte the padding should be filled with.
 	padByte := byte(' ')
 	if f.zero {
 		padByte = byte('0')
 	}
 	// Fill padding with padByte.
-	padding := buf[oldLen:newLen]
-	for i := range padding {
-		padding[i] = padByte
+	for i := 0; i < n; i++ {
+		f.buf.writeByte(padByte)
 	}
-	*f.buf = buf[:newLen]
 }
 
 // pad appends b to f.buf, padded on left (!f.minus) or right (f.minus).
@@ -401,19 +396,20 @@
 		f.writePadding(f.wid - width)
 	}
 	// Write the encoding directly into the output buffer.
-	buf := *f.buf
 	if f.sharp {
 		// Add leading 0x or 0X.
-		buf = append(buf, '0', digits[16])
+		f.buf.WriteByte('0')
+		f.buf.WriteByte(digits[16])
 	}
 	var c byte
 	for i := 0; i < length; i++ {
 		if f.space && i > 0 {
 			// Separate elements with a space.
-			buf = append(buf, ' ')
+			f.buf.WriteByte(' ')
 			if f.sharp {
 				// Add leading 0x or 0X for each element.
-				buf = append(buf, '0', digits[16])
+				f.buf.WriteByte('0')
+				f.buf.WriteByte(digits[16])
 			}
 		}
 		if b != nil {
@@ -422,9 +418,9 @@
 			c = s[i] // Take a byte from the input string.
 		}
 		// Encode each byte as two hexadecimal digits.
-		buf = append(buf, digits[c>>4], digits[c&0xF])
+		f.buf.WriteByte(digits[c>>4])
+		f.buf.WriteByte(digits[c&0xF])
 	}
-	*f.buf = buf
 	// Handle padding to the right.
 	if f.widPresent && f.wid > width && f.minus {
 		f.writePadding(f.wid - width)