ios - Latency in plotting microphone input -

i using avfoundation in order microphone input , ezaudio plot microphone input. have stripped down code basic , still latency, weird. code:

override func viewdidload() {     super.viewdidload()     //audio stuff     let buffersize: avaudioframecount = 2048      //plot properties     bufferplot.color = uicolor(red: 0.5, green: 0.0, blue: 0.0, alpha: 0)     bufferplot.backgroundcolor = uicolor(red: 1.0, green: 1.0, blue: 1.0, alpha: 0)     bufferplot.plottype = .buffer      //instantiate nodes     engine = avaudioengine()     input = engine.inputnode     mainmixer = engine.mainmixernode     //put tap on main mixer.      mainmixer.installtaponbus(0, buffersize: buffersize, format: mainmixer.inputformatforbus(0)) { (buffer: avaudiopcmbuffer!, time: avaudiotime!) -> void in          //change buffer size 2048         buffer.framelength = buffersize          //plotting         dispatch_async(dispatch_get_main_queue(), { () -> void in             self.bufferplot.updatebuffer(buffer.floatchanneldata.memory, withbuffersize: uint32(buffersize))         })     }      //start engine     var error: nserrorpointer = nserrorpointer()     engine.startandreturnerror(error) } 

am doing wrong?