From what I saw, URI

• Lowercases the scheme.
• Lowercases the domain name. (1)
• Removes the port if it's the default. (2)
• Removes port fields consisting of just ':'. (3)
• Adds trailing '/' if no path or query is specified. (6, partial)

• Doesn't do (4), (5), (7) and (8), but easy to do.
• Doesn't do (9) and (10), but might not be possible.
• Doesn't set the path to '/' if no path is specified and a query is specified. (6, partial)
• Doesn't normalize IP addresses in to dotted form.
• Doesn't remove the trailing '.' from domain names, if any.
• Doesn't touch the query.