Foo.of(List<Bar> bars) could be Foo.of(Iterable<Bar> bars)

[mcintyret]

The actual builder methods are already more lenient; can we make the of() static factories lenient too?

[mcintyret]

Also wouldn't say no to Foo.of(Bar... bars)

[markelliot]

as in #96 should probably remove of methods

[markelliot]

Also, Foo#of(Bar... bars) likely doesn't really make sense given objects may have more than one collection-style argument.