Actually - I can't yet say for sure, but it's very likely - the
EventedObject interface can probably be removed completely at some
point. It's only purpose was to provide the generic event ownership
mechanisms (acquire/release) and those have been removed on master.
It could be that there will be other methods that allow waiting on
multiple objects later, but these will not be needed by ConnectionPool.

But since this is not yet in a released version, it doesn't help that
much anyway.

Btw., if we assume that mysql-native in conjunction with vibe.d is
always built with DUB, instead of MySQLNNoVibeD, an additive approach
using the automatically defined Havevibe_d version could be used, too.