function start(code) {
    assert(code === codes.lessThan, 'expected `<`')
    effects.enter(types.autolink)
    effects.enter(types.autolinkMarker)
    effects.consume(code)
    effects.exit(types.autolinkMarker)
    effects.enter(types.autolinkProtocol)
    return open
  }
Start of an autolink.

```markdown
> | a<https://example.com>b
     ^
> | a<user@example.com>b
     ^
```

@type {State}