Annotated hex callback

### Things to check first

- [X] I have searched the existing issues and didn't find my feature already requested there

### Feature description

Please add the ability to register a visitor callback for each invocation and return of the parser or serializer.

### Use case

This would allow the callback function to record the type, its stack depth, and its position in the byte stream, enabling generation of the "Annotated hex" view of a CBOR blob:

Hex:
`82A1011901F4C077313938352D30342D31325432333A32303A35302E35325A`

Annotated Hex:
```
82 # array(2)
A1 # map(1)
01 # unsigned(1)
19 01F4 # unsigned(500)
C0 # tag(0)
77 # text(23)
313938352D30342D31325432333A32303A35302E35325A # "1985-04-12T23:20:50.52Z"
```