Untitled

public async Task<string> TimeInAsync(string instructorId, string firstName, string lastName)
{
    if (!await CanTimeInTodayAsync(instructorId))
    {
        throw new InvalidOperationException("You have already logged a Time In today.");
    }

    var timeIn = DateTime.Now;
    var timeEntry = new TimeEntry
    {
        instructorId = instructorId,
        FirstName = firstName,
        LastName = lastName,
        TimeIn = timeIn
    };

    var result = await _firebaseClient.Child("TimeEntries").PostAsync(timeEntry);
    return result.Key;
}