Hybrid Logical Clock in C#

HybridLogicalClock.cs

namespace HLC;

/// <summary>
/// The Hybrid Logical Clock. Contains both Physical Time and Logical Clock inside.
/// Grows monotonically, can be used to obtain unique timestamps even if called more often than
/// allowed by the physical clock precision.
/// 
/// <see cref="https://cse.buffalo.edu/tech-reports/2014-04.pdf"/>
/// </summary>
/// <remarks>Single-threaded use only!</remarks>
public struct HybridLogicalClock
{
    private const ulong BitMask = 0xFFL;

    public HybridLogicalClock()
    {
        _l = 0;
        _c = 0;
    }

    public ulong GetTimeStamp()
    {
        var l1 = _l;

        // clear out the last 16 bits off of physical timestamp
        var pt = (ulong)DateTime.Now.Ticks & ~BitMask;

        _l = Math.Max(l1, pt);
        if (_l == l1)
        {
            _c++;
        }
        else
        {
            _c = 0;
        }
        return _l | _c;
    }

    private ulong _l;
    private ushort _c;
}