build method
Generates the outputs for a given BuildStep.
Implementation
@override
FutureOr<void> build(BuildStep buildStep) {
return Future.wait(_builders
.where((builder) => builder.buildExtensions.keys
.any(buildStep.inputId.path.endsWith))
.map((builder) => builder.build(buildStep))
.whereType<Future<void>>())
.then((_) {});
}