code: func LoadDuration(d *duration.Duration, v time.Duration) *duration.Duration {
  	if d == nil {
  		if v == 0 {
  			return nil
  		}
  
  		d = &duration.Duration{}
  	}
  
  	nanos := v.Nanoseconds()
  
  	d.Seconds = nanos / nanosecondsInASecond
  	d.Nanos = int32(nanos % nanosecondsInASecond)
  	return d
  }
docs: // LoadDuration replaces the value in the supplied Duration with the specified
  // value.
  //
  // If the supplied Duration is nil and the value is non-zero, a new Duration
  // will be generated. The populated Duration will be returned.