Kendall Jenner toyed with skipping the Met Gala this year. She’d already gone 11 times (an even more impressive attendance rate when you recall that the Jenner/Kardashian clan was unofficially blacklisted until 2013), so she mused to her team that she might sit this one out. But if I do go, Jenner proposed, “I want to have a Zac moment.”   The next day, the model/influencer/Tequila magnate received an effusive letter from a man she admired but had never met. Zac Posen , who was unaware of her reticence, wanted to know if she would like him to dress and accompany her up the Museum’s granite staircase on the first Monday in May.   Posen has never been a shy guy. Not when discussing his aspirations, his aesthetic or his belief in his own talent, for good reason. With his Charles Jamesian penchant for unapologetic glamour, Posen was quickly hailed at the start of the millennium as a white-hot one to watch.…