Runtime: ForEach or Select void to do some logic and continue with the same collection

[Thaina]

I'm not sure we should add new API or just use Select. But it would be the same argument

```C#
IEnumerable Select(this IEnumerable list,Action action);
IEnumerable Select(this IEnumerable list,Action action);

or

IEnumerable ForEach(this IEnumerable list,Action action);
IEnumerable ForEach(this IEnumerable list,Action action);
```

This let us split iteration logic easier. We could do something before Where clause. We could split it out from Where without the need to return each item unneccessary

[svick]

I don't think LINQ should encourage side-effects, especially not in the middle of a query.

Though if this method is added, it should probably stay consistent with Rx, which calls this method Do().

[mikem8361]

Please ignore the PRs/merges dotnet/corefx#31991. Wrong issue.

[stephentoub]

I don't think LINQ should encourage side-effects, especially not in the middle of a query.

Agreed. This goes against the general approach we've tried to maintain with LINQ.