random method
Generates a random integer between 0 (inclusive) and this value (exclusive),
with an optional seed for reproducibility.
Throws RangeError if this value is less than 1.
Implementation
int random([int? seed]) {
if (this < 1) {
throw RangeError('Upper bound must be at least 1.');
}
return math.Random(seed).nextInt(toInt());
}