// concurrently, check for it before we
				// write the filler byte.
				select {
				case err := <-doneCh:
					if err != nil {
						write([]byte{1})
						write([]byte(err.Error()))
					} else {
						write([]byte{0})
					}
					return
				default:
				}

				// Response not ready, write a filler byte.
				write([]byte{32})
				if canWrite {
					w.(http.Flusher).Flush()

	// map header, size 14
	// write "ReplicatedSize"
	err = en.Append(0x8e, 0xae, 0x52, 0x65, 0x70, 0x6c, 0x69, 0x63, 0x61, 0x74, 0x65, 0x64, 0x53, 0x69, 0x7a, 0x65)
	if err != nil {
		return
	}
	err = en.WriteInt64(z.ReplicatedSize)
	if err != nil {
		err = msgp.WrapError(err, "ReplicatedSize")
		return
	}
	// write "ReplicaSize"

	}
	if reply = locksHeld == WriteLock; !reply { // Unless it is a write lock
		return false, fmt.Errorf("Unlock attempted on a read locked entity: %s (%d read locks active)", args.Resources[0], locksHeld)
	}
	delete(l.lockMap, args.Resources[0]) // Remove the write lock
	return true, nil
}

const ReadLock = 1

	writer := newBitrotWriter(disk, "", volume, filePath, 35, bitrotAlgo, 10)

	_, err = writer.Write([]byte("aaaaaaaaaa"))
	if err != nil {
		t.Fatal(err)
	}
	_, err = writer.Write([]byte("aaaaaaaaaa"))
	if err != nil {
		t.Fatal(err)
	}
	_, err = writer.Write([]byte("aaaaaaaaaa"))
	if err != nil {
		t.Fatal(err)
	}
	_, err = writer.Write([]byte("aaaaa"))
	if err != nil {
		t.Fatal(err)
	}

## Cluster probe

### Cluster-writeable probe

The reply is '200 OK' if cluster has write quorum if not it returns '503 Service Unavailable'.

```
curl http://minio1:9001/minio/health/cluster
HTTP/1.1 503 Service Unavailable
Accept-Ranges: bytes
Content-Length: 0
Server: MinIO
Vary: Origin
X-Amz-Bucket-Region: us-east-1
X-Minio-Write-Quorum: 3
X-Amz-Request-Id: 16239D6AB80EBECF
X-Xss-Protection: 1; mode=block

func NewLRWMutex() *LRWMutex {
	return &LRWMutex{}
}

// Lock holds a write lock on lm.
//
// If the lock is already in use, the calling go routine
// blocks until the mutex is available.
func (lm *LRWMutex) Lock() {
	const isWriteLock = true
	lm.lockLoop(context.Background(), lm.id, lm.source, math.MaxInt64, isWriteLock)
}

// GetLock tries to get a write lock on lm before the timeout occurs.

			mustGetPutObjReader(b, bytes.NewReader(textData), int64(len(textData)), md5hex, sha256hex), ObjectOptions{})
		if err != nil {
			b.Fatal(err)
		}
		if objInfo.ETag != md5hex {
			b.Fatalf("Write no: %d: Md5Sum mismatch during object write into the bucket: Expected %s, got %s", i+1, objInfo.ETag, md5hex)
		}
	}
	// Benchmark ends here. Stop timer.
	b.StopTimer()
}

// Benchmark utility functions for ObjectLayer.PutObjectPart().

func (z jentry) EncodeMsg(en *msgp.Writer) (err error) {
	// map header, size 3
	// write "obj"
	err = en.Append(0x83, 0xa3, 0x6f, 0x62, 0x6a)
	if err != nil {
		return
	}
	err = en.WriteString(z.ObjName)
	if err != nil {
		err = msgp.WrapError(err, "ObjName")
		return
	}
	// write "vid"
	err = en.Append(0xa3, 0x76, 0x69, 0x64)
	if err != nil {
		return
	}

func (z *listPathOptions) EncodeMsg(en *msgp.Writer) (err error) {
	// map header, size 19
	// write "ID"
	err = en.Append(0xde, 0x0, 0x13, 0xa2, 0x49, 0x44)
	if err != nil {
		return
	}
	err = en.WriteString(z.ID)
	if err != nil {
		err = msgp.WrapError(err, "ID")
		return
	}
	// write "Bucket"
	err = en.Append(0xa6, 0x42, 0x75, 0x63, 0x6b, 0x65, 0x74)
	if err != nil {
		return
	}

	buf := new(bytes.Buffer)
	binary.Write(buf, binary.BigEndian, uint32(totalLength))
	binary.Write(buf, binary.BigEndian, uint32(headerLength))
	prelude := buf.Bytes()
	binary.Write(buf, binary.BigEndian, crc32.ChecksumIEEE(prelude))
	buf.Write(header)
	if payload != nil {
		buf.Write(payload)
	}
	message := buf.Bytes()
	binary.Write(buf, binary.BigEndian, crc32.ChecksumIEEE(message))

	return buf.Bytes()