Time since a certain period

TimeSince.cs

public struct TimeSince
{
    public TimeSince(DateTime? from = default)
    {
        From = from.HasValue ? from.Value : DateTime.Now;
    }

    readonly DateTime From;
    public static implicit operator float(TimeSince @this) => (float)((TimeSpan)@this).TotalSeconds;
    public static implicit operator TimeSince(float @this) => new TimeSince(DateTime.Now.AddSeconds(@this));
    public static implicit operator TimeSpan(TimeSince @this) => (DateTime.Now - @this.From);
    public static implicit operator DateTime(TimeSince @this) => @this.From;
}