now unbuffered, with capacity 0.
The main effect of this change is that Go now guarantees
that for any call to a `Reset` or `Stop` method, no stale values
prepared before that call will be sent or received after the call.
Earlier versions of Go used channels with a one-element buffer,
making it difficult to use `Reset` and `Stop` correctly.
A visible effect of this change is that `len` and `cap` of timer channels

	}
	r.i += int64(m)
	n = int64(m)
	if m != len(b) && err == nil {
		err = io.ErrShortWrite
	}
	return
}

// Reset resets the [Reader.Reader] to be reading from b.
func (r *Reader) Reset(b []byte) { *r = Reader{b, 0, -1} }

// NewReader returns a new [Reader.Reader] reading from b.

			realSize := hdr.Size
			hdr.Size = 0 // Encoded size; does not account for encoded sparse map
			for _, s := range spd {
				hdr.Size += s.Length
			}
			copy(blk.V7().Size(), zeroBlock[:]) // Reset field
			f.formatNumeric(blk.V7().Size(), hdr.Size)
			f.formatNumeric(blk.GNU().RealSize(), realSize)
		}
	*/
	blk.setFormat(FormatGNU)
	if err := tw.writeRawHeader(blk, hdr.Size, hdr.Typeflag); err != nil {

	}
}

func TestReaderReset(t *testing.T) {
	r := NewReader([]byte("世界"))
	if _, _, err := r.ReadRune(); err != nil {
		t.Errorf("ReadRune: unexpected error: %v", err)
	}

	const want = "abcdef"
	r.Reset([]byte(want))
	if err := r.UnreadRune(); err == nil {
		t.Errorf("UnreadRune: expected error, got nil")
	}
	buf, err := io.ReadAll(r)
	if err != nil {
		t.Errorf("ReadAll: unexpected error: %v", err)
	}

		t.Errorf("buf = %q; want foo", buf)
	}

	r.Reset(strings.NewReader("bar bar"))
	checkAll(r, "bar bar")

	*r = Reader{} // zero out the Reader
	r.Reset(strings.NewReader("bar bar"))
	checkAll(r, "bar bar")

	// Wrap a reader and then Reset to that reader.
	r.Reset(strings.NewReader("recur"))
	r2 := NewReader(r)
	checkAll(r2, "recur")
	r.Reset(strings.NewReader("recur2"))
	r2.Reset(r)

	buf := NewBuffer(make([]byte, n))
	for i := 0; i < b.N; i++ {
		buf.Reset()
		for i := 0; i < n; i++ {
			buf.WriteByte('x')
		}
	}
}

func BenchmarkWriteRune(b *testing.B) {
	const n = 4 << 10
	const r = '☺'
	b.SetBytes(int64(n * utf8.RuneLen(r)))
	buf := NewBuffer(make([]byte, n*utf8.UTFMax))
	for i := 0; i < b.N; i++ {
		buf.Reset()
		for i := 0; i < n; i++ {
			buf.WriteRune(r)
		}
	}
}

			c = ' ' // Treat the checksum field itself as all spaces.
		}
		unsigned += int64(c)
		signed += int64(int8(c))
	}
	return unsigned, signed
}

// reset clears the block with all zeros.
func (b *block) reset() {
	*b = block{}
}

type headerV7 [blockSize]byte

func (h *headerV7) name() []byte     { return h[000:][:100] }
func (h *headerV7) mode() []byte     { return h[100:][:8] }

### Go 1.23

Go 1.23 changed the channels created by package time to be unbuffered
(synchronous), which makes correct use of the [`Timer.Stop`](/pkg/time/#Timer.Stop)
and [`Timer.Reset`](/pkg/time/#Timer.Reset) method results much easier.
The [`asynctimerchan` setting](/pkg/time/#NewTimer) disables this change.
There are no runtime metrics for this change,

	conf.Fprint(&buf, fset, f.AST)

	return buf.String()
}

var gofmtBuf strings.Builder

// gofmt returns the gofmt-formatted string for an AST node.
func gofmt(n interface{}) string {
	gofmtBuf.Reset()
	err := printer.Fprint(&gofmtBuf, fset, n)
	if err != nil {
		return "<" + err.Error() + ">"
	}
	return gofmtBuf.String()
}

// gofmtLineReplacer is used to put a gofmt-formatted string for an

func (b *Buffer) Truncate(n int) {
	if n == 0 {
		b.Reset()
		return
	}
	b.lastRead = opInvalid
	if n < 0 || n > b.Len() {
		panic("bytes.Buffer: truncation out of range")
	}
	b.buf = b.buf[:b.off+n]
}

// Reset resets the buffer to be empty,
// but it retains the underlying storage for use by future writes.
// Reset is the same as [Buffer.Truncate](0).
func (b *Buffer) Reset() {
	b.buf = b.buf[:0]
	b.off = 0