getInstance static method
Returns a cached or new instance of MuscleHelper for the given muscle and svgPathReader.
Implementation
static MuscleHelper getInstance(Muscle muscle, SvgPathReader svgPathReader) {
final key = (muscle, svgPathReader._assetType);
_instances.putIfAbsent(
key,
() => MuscleHelper._(muscle.name, svgPathReader),
);
return _instances[key]!;
}