How to hide MPMediaItemPropertyPlaybackDuration slider from locked screen and Control Center?

I'm working on online radio player and need some help. When I set MPNowPlayingInfoCenter.defaultCenter().nowPlayingInfo I have title, controls and playback duration slider. I don't need this slider because I have no info about playback duration and moreover it is not a very good looking control. Can somebody prompt me how to hide playback duration slider? And one more question: since the app is online radio player, the user have no ability to forward or rewind the playback, so I want to hide this controls from locked screen and Control Center either. By the way I'm using Swift. Thanks in advance!