In the history of the United States, only two individuals have had the dubious honor of being restrained with this particular device: one being the Chainsaw Maniac, the other the infamous Cannibal Doctor. And now, there was a third -- Zhang Ziwen, the master of Chinese martial arts. The metal pole spanning three meters was clearly a safety measure. The fact that the suspect was restrained in this way underscored how dangerous the police considered him to be. In their eyes, he was already a serious repeat offender…