channels[constants.StreamStdIn] = readChannel(opts.Stdin)
	channels[constants.StreamStdOut] = writeChannel(opts.Stdout)
	channels[constants.StreamStdErr] = writeChannel(opts.Stderr)
	channels[constants.StreamErr] = wsstream.WriteChannel
	channels[constants.StreamResize] = wsstream.ReadChannel
	return channels
}

// readChannel returns wsstream.ReadChannel if real is true, or wsstream.IgnoreChannel.

type codecType int

const (
	rawCodec codecType = iota
	base64Codec
)

type ChannelType int

const (
	IgnoreChannel ChannelType = iota
	ReadChannel
	WriteChannel
	ReadWriteChannel
)

// IsWebSocketRequest returns true if the incoming request contains connection upgrade headers
// for WebSockets.
func IsWebSocketRequest(req *http.Request) bool {