measure method
Measures the score for the benchmark and returns it.
Implementation
double measure() {
setup();
// Warmup for at least 100ms. Discard result.
_measureForImpl(warmup, 100);
// Run the benchmark for at least 2000ms.
var result = _measureForImpl(exercise, _minimumMeasureDurationMillis);
teardown();
return result.score;
}