function start(code) {
    assert(code === codes.backslash, 'expected `\\`')
    effects.enter(types.characterEscape)
    effects.enter(types.escapeMarker)
    effects.consume(code)
    effects.exit(types.escapeMarker)
    return inside
  }
Start of character escape.

```markdown
> | a\*b
     ^
```

@type {State}