ref and out parameters in C# and cannot be marked as variant

Question

What does the statement mean?

From here

ref and out parameters in C# and cannot be marked as variant.

1) Does it mean

Answer 1

But, the following code can be compiled:

interface IFoo
{
    T Get();

    //bool TryGet(out T value); // doesn't work: Invalid variance: The type parameter 'T' must be invariantly valid on 'IFoo.TryGet(out T)'. 'T' is covariant.

    bool TryGet(Action value); // works!
}