Package not available after install

[raspberrypisig]

• Flutter version 1.3.14-pre.65 at ~/Developer/flutter
• Framework revision 1b282b0e80 (4 days ago), 2019-03-24 05:18:43 -0400
• Engine revision d2bba21af2
• Dart version 2.2.1 (build 2.2.1-dev.2.0 None)

Followed installation instruction (flutter packages get).
I can see the package in <flutter_dir>/.pub-cache/hosted/pub.dartlang.org/multicast_lock-0.0.5

but not in <flutter_dir>/packages/multicast_lock

And as a result

import 'package:multicast_lock/multicast_lock.dart';

doesn't work.

Moving the package there doesn't solve the issue.

Don't know enough about flutter packages to resolve issue myself.