Callback plugin didn't work with Ansible v2.0

I am using Ansible v2.0 and using this plugin, which shows the time that each task consume and here is my directory struture:

.
├── aws.yml
├── callback_plugins
│   ├── profile_tasks.py  
├── inventory
│   └── hosts
├── roles
│   ├── ec2instance
│   │   ├── defaults
│   │   │   └── main.yml
│   │   └── tasks
│   │       └── main.yml
│   ├── ec2key
│   │   ├── defaults
│   │   │   └── main.yml
│   │   └── tasks
│   │       └── main.yml
│   ├── ec2sg
│   │   ├── defaults
│   │   │   └── main.yml
│   │   └── tasks
│   │       └── main.yml
│   ├── elb
│   │   ├── defaults
│   │   │   └── main.yml
│   │   └── tasks
│   │       └── main.yml
│   ├── rds
│   │   ├── defaults
│   │   │   └── main.yml
│   │   └── tasks
│   │       └── main.yml
│   └── vpc
│       ├── defaults
│       │   └── main.yml
│       └── tasks
│           └── main.yml
└── secret_vars
    ├── backup.yml
    └── secret.yml

But when I run the playbook, it didn’t show the result, can you please point me that where I am making mistake.

the plugin is included with ansible 2.0 and as most of those included
it requires whitelisting in ansible.cfg, don't copy it to custom
folders, you can simply enable it doing the following:

ansible.cfg:
callback_whitelist = profile_tasks

Thanks Brian, work perfectly.