I have a list of time sheet entries and usually each user will have multiple entries for the same day because they clock in and out during lunch.

My time sheet class looks like this:

```
public class TimeSheetEntry
{
    public Guid EmployeeId { get; set; }
    public DateTime ClockInTimeStamp { get; set; }
    public DateTime ClockOutTimeStamp { get; set; }
}

```

I want to determine the number of days a user has worked. I want to do this using the `ClockInTimeStamp` property by counting the unique days in my `List<TimeSheetEntry>()`.

How do I get the number of unique days in this list using LINQ?