code: func (q *Quantity) AsInt64() (int64, bool) {
  	if q.d.Dec != nil {
  		return 0, false
  	}
  	return q.i.AsInt64()
  }
docs: // AsInt64 returns a representation of the current value as an int64 if a fast conversion
  // is possible. If false is returned, callers must use the inf.Dec form of this quantity.