```go
package main

import (
	"fmt"

	"github.com/smallnest/ringbuffer"
)

func main() {
	rb := ringbuffer.New(1024)

	// write
	rb.Write([]byte("abcd"))
	fmt.Println(rb.Length())
	fmt.Println(rb.Free())

	// read
	buf := make([]byte, 4)
	rb.Read(buf)
	fmt.Println(string(buf))
}
```

It is possible to use an existing buffer with by replacing `New` with `NewBuffer`.

	// Embed a "fake" exit code in the middle to check that we don't get caught on it.
	pre := "abc" + exitStr + "123def"
	text := pre + exitStr + `1`
	for i := 0; i < len(text); i++ {
		_, err := f.Write([]byte{text[i]})
		if err != nil {
			t.Fatal(err)
		}
	}

	// The "pre" output should all have been flushed already.
	if want, got := pre, out.String(); want != got {

	// string "set"
	o = append(o, 0xa3, 0x73, 0x65, 0x74)
	o = msgp.AppendInt(o, z.set)
	return
}

// UnmarshalMsg implements msgp.Unmarshaler
func (z *listPathOptions) UnmarshalMsg(bts []byte) (o []byte, err error) {
	var field []byte
	_ = field
	var zb0001 uint32
	zb0001, bts, err = msgp.ReadMapHeaderBytes(bts)
	if err != nil {
		err = msgp.WrapError(err)
		return
	}
	for zb0001 > 0 {
		zb0001--

	v := ChecksumInfo{}
	b.ReportAllocs()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		v.MarshalMsg(nil)
	}
}

func BenchmarkAppendMsgChecksumInfo(b *testing.B) {
	v := ChecksumInfo{}
	bts := make([]byte, 0, v.Msgsize())
	bts, _ = v.MarshalMsg(bts[0:0])
	b.SetBytes(int64(len(bts)))
	b.ReportAllocs()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		bts, _ = v.MarshalMsg(bts[0:0])
	}
}

	}
	return buf, stat.ModTime().UTC(), err
}

func (s *xlStorage) readMetadata(ctx context.Context, itemPath string) ([]byte, error) {
	return xioutil.WithDeadline[[]byte](ctx, globalDriveConfig.GetMaxTimeout(), func(ctx context.Context) ([]byte, error) {
		buf, _, err := s.readMetadataWithDMTime(ctx, itemPath)
		return buf, err
	})
}

		tokenErr.Description = "The request route included in the request is invalid"
		writeErrorResponse(ctx, w, tokenErr, r.URL)
		return
	}

	if subtle.ConstantTimeCompare([]byte(resp.Header.Get(xhttp.AmzRequestToken)), []byte(eventData.GetObjectContext.OutputToken)) != 1 {
		tokenErr := errorCodes.ToAPIErr(ErrInvalidToken)
		tokenErr.Description = "The request token included in the request is invalid"

	}

	if _, ok := claims[policy.SessionPolicyName]; ok {
		owner = false
	}

	return cred, owner, ErrNone
}

// sumHMAC calculate hmac between two input byte array.
func sumHMAC(key []byte, data []byte) []byte {
	hash := hmac.New(sha256.New, key)
	hash.Write(data)
	return hash.Sum(nil)
}

// extractSignedHeaders extract signed headers from Authorization header

    assertHash32(0x5BD90FD9, ADLER_32, "The quick brown fox jumps over the lazy cog");
  }

  private static void assertChecksum(ImmutableSupplier<Checksum> supplier, String input) {
    byte[] bytes = HashTestUtils.ascii(input);

    Checksum checksum = supplier.get();
    checksum.update(bytes, 0, bytes.length);
    long value = checksum.getValue();

    String toString = "name";

	// look for directoryEndSignature in the last 1k, then in the last 65k
	var buf []byte
	var directoryEndOffset int64
	for i, bLen := range []int64{1024, 65 * 1024} {
		if bLen > size {
			bLen = size
		}
		buf = make([]byte, int(bLen))
		if _, err := r.ReadAt(buf, size-bLen); err != nil && err != io.EOF {
			return nil, 0, err
		}

    val payload = Buffer()
    while (payload.completeSegmentByteCount() <= PAYLOAD_BYTE_MAX) {
      payload.writeByte('0'.code)
    }
    serverWriter.writeMessageFrame(OPCODE_BINARY, payload.snapshot())

    // Write directly to the unbuffered sink. This ensures it will become single frame.
    assertData("827e") // 'e' == 4-byte follow-up length.