However, I think this is all moot, druntime is the same as Tango.
Moot you mean debatable? Or irrelevant :) Thanks to your explanations, I understand now that the dev tried to imitate a Tango feature with very old D1 code. This is 2005/2009 code
And as pointed out by IGotD-, better not to mess around with synch / reinvent the wheel. I will trash this class. Still learning a lot, thank you guys.
