I very often want to make an assertion about every member of a collection.
You can use .Should().OnlyContain() but I'd like to be able to use your lovely library of helper assertions.

e.g. I'd like to be able to write:
myStrings.Should().All().StartWith("Hello");

It feels like it ought to be relatively achievable?
Roughly speaking .All() would need to return an object that looked the same as a .Should() of the Collection contents but which passes all of its implementations down to an inner .Should() against each of the elements.

First Question: Would you be happy with this functionality existing?

Second Question: Is this something that you'd be likely to implement any time soon?
If not, would you accept a PR for it? And do you think such a change would be tractable to an experienced .NET programmer who's never looked inside your codebase before?