Gauge constructor

Implementation

Gauge(String name, String description, this.min, this.max)
    : super(name, description) {
  if (min is! double) {
    throw new ArgumentError('min must be a double');
  }
  if (max is! double) {
    throw new ArgumentError('max must be a double');
  }
  if (!(min < max)) {
    throw new ArgumentError('min must be less than max');
  }
  _value = min;
}