The returned array contains the following keys:
* "scheme": The scheme part before the "://";
* "path": The path part after the "://".
The URI must fulfill a few constraints:
* the scheme must consist of alphabetic characters only;
* the scheme may be omitted. Then "://" must be omitted too;
* the path must not be empty;
* the path must start with a forward slash ("/").
If any of these constraints is not fulfilled, an
{@link InvalidUriException} is thrown.
