in lib/pool.dart [297:307]
Future<PoolResource> _runOnRelease(Function() onRelease) {
Future.sync(onRelease).then((value) {
_onReleaseCompleters.removeFirst().complete(PoolResource._(this));
}).catchError((Object error, StackTrace stackTrace) {
_onReleaseCompleters.removeFirst().completeError(error, stackTrace);
});
var completer = Completer<PoolResource>.sync();
_onReleaseCompleters.add(completer);
return completer.future;
}