inc method

void inc([
  1. double amount = 1
])

Increment the value of the counter with labels by amount. Increments by one, if no amount is provided.

Implementation

void inc([double amount = 1]) {
  if (amount <= 0) {
    throw ArgumentError.value(amount, 'amount', 'Must be greater than zero.');
  }

  _value += amount;
}