Transform block silently swallow exeptions.

transform_bug.dart

#import("dart:io");
Future getFuture() {
  var completer = new Completer();
  new Timer(100,(timer) => completer.complete(true));
  return completer.future;
}
void main() {  
  getFuture().chain((_) {
    print("Before exception in chain block");
    throw 'Error in chain block';
    print("After exception in chain block");
    return getFuture();
  }).then((_) {
    print("Before exception in then block");
    throw 'Error in then block';
    print("After exception in then block");
  });    
}