# tag abstract method

StartupStep tag(

1. String key, {
2. String? value,
3. String supplied()?,

})

Attaches a static key/value tag to this step.

Tags provide contextual metadata like:

- `pod.name`: `dataSource`
- `phase`: `initialization`

### Example:

    step.tag('pod.name', value: 'userService');
    step.tag('pod.name', supplied: () => 'userService');

## Implementation

    StartupStep tag(String key, {String? value, String Function()? supplied});