IPv6 support?

Hi there! This is pretty nifty. I found this after looking for ways to avoid contention on the inner select lock. However, it looks like the 'inet6' option is unsupported in gen_socket:connect. Any plans to add this or is there another way to accomplish this? Also was curious about the {packet, 4} option.

Start by reviewing the gen_socket:connect entry point and how it handles the 'inet6' and {packet, 4} options. Determine the current support and expected behavior from the existing implementation; done should mean IPv6 handling is supported or the limitation and alternative are clearly documented.

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