*     [Section 7.4 of RFC 6455](http://tools.ietf.org/html/rfc6455#section-7.4) or `0`.
   * @param reason Reason for shutting down or `null`.
   */
  @Throws(IOException::class)
  fun writeClose(
    code: Int,
    reason: ByteString?,
  ) {
    var payload = ByteString.EMPTY
    if (code != 0 || reason != null) {
      if (code != 0) {
        validateCloseCode(code)
      }
      payload =

        synchronized(this) {
          queueSize -= message.data.size.toLong()
        }
      } else if (messageOrClose is Close) {
        val close = messageOrClose
        writer!!.writeClose(close.code, close.reason)

        // We closed the writer: now both reader and writer are closed.
        if (sendOnClosed) {
          listener.onClosed(this, receivedCloseCode, receivedCloseReason!!)
        }

	UserTags string

	// List of individual parts, maximum size of upto 10,000
	Parts []ObjectPartInfo `json:"-"`

	// Implements writer and reader used by CopyObject API
	Writer       io.WriteCloser `json:"-" msg:"-"`
	Reader       *hash.Reader   `json:"-" msg:"-"`
	PutObjReader *PutObjReader  `json:"-" msg:"-"`

	metadataOnly bool
	versionOnly  bool // adds a new version, only used by CopyObject