function send(message, options) {
            return new Promise(function(resolve, reject) {
              switch (ws.readyState) {
              case WebSocket.OPENING:
                // This should never happen.
                log.warn('Unable to send to OPENING client "%s"', id)
                break
              case WebSocket.OPEN:
                // This is what SHOULD happen.
                ws.send(message, options, function(err) {
                  return err ? reject(err) : resolve()
                })
                break
              case WebSocket.CLOSING:
                // Ok, a 'close' event should remove the client from the set
                // soon.
                log.debug('Websocket CLOSING: "%s"', id)
                break
              case WebSocket.CLOSED:
                // This should never happen.
                webdriverAgent.removeListener('frame', emitFrame)
                webdriverAgent.removeListener('orientation', emitOrientation)
                webdriverAgent.removeListener('actionId', emitActionId)
                log.warn('Unable to send to CLOSED client "%s"', id)
                break
              }
            })
          }