fails:Mutex#try_lock returns true if lock can be aquired immediately
fails:Mutex#try_lock actually locks
fails:Mutex#try_lock returns false if lock can not be aquired immediately
fails:"Mutex#try_lock returns true if lock can be aquired immediately"
fails:"Mutex#try_lock actually locks"
fails:"Mutex#try_lock returns false if lock can not be aquired immediately"
