Misleading error message when using non-`en0` interface on macOS

[fwcd]

Calling local_ip() on macOS when using e.g. en1 instead of en0 (with the latter not being assigned an IP at all) yields the following, slightly misleading error message:

PlatformNotSupported("macos")

Perhaps the library could try en0, en1, ... in order until it finds an IP address and, if not, throw an error along the lines of "No interface with an IP address found"?

[LeoBorai]

Hi @fwcd, thanks for opening this issue!

I agree, the current error message it's confusing. Let me check on other approaches, when I updated the Linux approach to use neli I wondered if there's any similar approach for macOS that doesn't rely on interface name.

As of today errors are standardized which means that I have to keep all errors the same for supported targets, we could have complaints on match cases when building on macOS for multi target projects if I added another error message for this specialized scenario.

I think I could, research on other ways to retrieve the default gateway on macOS, and then, update the approach so we don't rely on the interface name anymore.

What do you think?