code: func NewHtbClass(attrs ClassAttrs, cattrs HtbClassAttrs) *HtbClass {
  	mtu := 1600
  	rate := cattrs.Rate / 8
  	ceil := cattrs.Ceil / 8
  	buffer := cattrs.Buffer
  	cbuffer := cattrs.Cbuffer
  
  	if ceil == 0 {
  		ceil = rate
  	}
  
  	if buffer == 0 {
  		buffer = uint32(float64(rate)/Hz() + float64(mtu))
  	}
  	buffer = uint32(Xmittime(rate, buffer))
  
  	if cbuffer == 0 {
  		cbuffer = uint32(float64(ceil)/Hz() + float64(mtu))
  	}
  	cbuffer = uint32(Xmittime(ceil, cbuffer))
  
  	return &HtbClass{
  		ClassAttrs: attrs,
  		Rate:       rate,
  		Ceil:       ceil,
  		Buffer:     buffer,
  		Cbuffer:    cbuffer,
  		Quantum:    10,
  		Level:      0,
  		Prio:       0,
  	}
  }
docs: // NewHtbClass NOTE: function is in here because it uses other linux functions