- Updated error handling to use the error return value for resource closures in tests and functions, ensuring proper error reporting.
- Replaced direct calls to `Close()` with deferred functions that handle errors gracefully.
- Improved readability by using `strings.ReplaceAll` instead of `strings.Replace` for string manipulation.
- Enhanced network connection handling by adding default cases for unsupported network types.
- Updated HTTP response handling to use the appropriate status codes and error messages.
- Removed unused variables and commented-out code to clean up the codebase.
https://datatracker.ietf.org/doc/html/rfc1939#page-6
> If an argument was given and the POP3 server issues a positive response with a line containing information for that message. This line is called a "scan listing" for that message.
