code: func (node *ClientNode) updateParams(params ServerParams, now mclock.AbsTime) {
  	diff := params.BufLimit - node.params.BufLimit
  	if int64(diff) > 0 {
  		node.bufValue += diff
  	} else if node.bufValue > params.BufLimit {
  		node.bufValue = params.BufLimit
  	}
  	node.cm.updateParams(node, params, now)
  }
docs: // updateParams updates the flow control parameters of the node