Unrestricted types, only checking member extensions

[zms9110750]

be similar to
arr[ .. ]only need CountandSlice.
foreach only need GetEnumerator,and no matter what this method returns, as long as the return value hasCurrent ,MoveNext.

Many engines have a vector. If I write extension methods for them, only for this type.
I'm not sure if using interface bridging will cause boxing or any other performance issues.
I think it would be great if the extension method written could be used for any type with X and Y members.

[HaloFour]

I believe that would fall under extension implementation: #5497

I expect that it would require at least specifying the extension, although perhaps the compiler can automatically wire up the compatible members.