code: func (c *Context) Stream(step func(w io.Writer) bool) bool {
  	w := c.Writer
  	clientGone := w.CloseNotify()
  	for {
  		select {
  		case <-clientGone:
  			return true
  		default:
  			keepOpen := step(w)
  			w.Flush()
  			if !keepOpen {
  				return false
  			}
  		}
  	}
  }
docs: // Stream sends a streaming response and returns a boolean
  // indicates "Is client disconnected in middle of stream"