require method
Throws MssqlCapabilityException unless available holds.
The one place a capability turns into a refusal, so every message names the feature, what it needs and what was found instead.
Implementation
void require(
// ignore: avoid_positional_boolean_parameters
bool available, {
required String feature,
required String requires,
}) {
if (available) return;
throw MssqlCapabilityException(
feature: feature,
requires: requires,
found: description,
);
}