Why didn't we overload WithIPAddress for multicast?

[mwelzl]

From the review by Lars Eggert, COMMENT part:

Section 6.1.1, paragraph 4

    RemoteSpecifier.WithMulticastGroupIP(GroupAddress)

It's a design choice to not overload WithIPAddress here and instead
define WithMulticastGroupIP. I'd have overloaded, in order to avoid
the need for error handling if the wring type of IP address is passed
in.

[mwelzl]

There's a need for this when using SSN.

[mwelzl]

... that need should be explained.