the busName and interfacePath types transparently cast down to a string,
(but not the other way around) so they are a perfect upgrade to
type-safety. The only downside to them is that templates can often get
them wrong. std.conv.to will return with a cast(T) prefix, which could
slightly break existing code.
I think the type-safety advantages are outweighing this corner case
though. The current API has been fully upgraded and examples still run
and work.
