Parsing string with multiple HTTP requests

Could you please clarify what the behaviour is when execute() gets passed a string with two (or even more) HTTP requests directly behind each other (seperated by "\r\n\r\n").
In my example

```
pars.get_headers()["HOST"]
```

returned the Host field of **both** requests seperated with a comma (although the hosts were the same).

Interestingly

```
pars.get_url()
```

returned just the URL of the **second** request.

Start by reproducing the example through execute(), then inspect how get_headers() and get_url() handle a string containing multiple HTTP requests separated by "\r\n\r\n". Determine and document the expected behavior for multiple requests, including whether both requests should be parsed and how the returned headers and URL should be represented.

Scritto dal modello di indicizzazione a partire dal testo della issue.