0917 error code about addObserver

2019-09-17 21:02:37.664793+0800 m3u8[13018:419015] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<VLCMediaPlayer 0x6000004847e0> addObserver:<m3u8.RecordListViewController 0x7fb4bd41a910> forKeyPath:@"currentItem.loadedTimeRanges" options:1 context:0x0] was sent to an object that is not KVC-compliant for the "currentItem" property.'
*** First throw call stack:
(
	0   CoreFoundation                      0x000000010d2168db __exceptionPreprocess + 331
	1   libobjc.A.dylib                     0x000000010c7c1ac5 objc_exception_throw + 48
	2   CoreFoundation                      0x000000010d216735 +[NSException raise:format:] + 197
	3   Foundation                          0x000000010bfa1706 -[NSObject(NSKeyValueObserverRegistration) addObserver:forKeyPath:options:context:] + 458
	4   m3u8                                0x0000000105b5160c $s4m3u824RecordListViewControllerC15setAndPlayViedo9streamUrlySS_tF + 3244
	5   m3u8                                0x0000000105b50887 $s4m3u824RecordListViewControllerC13getChannelEpg9channelIDySi_tFyycfU_ + 135
	6   m3u8                                0x0000000105b5273d $s4m3u824RecordListViewControllerC13getChannelEpg9channelIDySi_tFyycfU_TA + 13
	7   m3u8                                0x0000000105b53940 $s4m3u824RecordListViewControllerC03getB3Url12tuner_epg_id10completionySi_yyctFy9Alamofire12DataResponseVyypGcfU_ + 3104
	8   m3u8                                0x0000000105b58991 $s4m3u824RecordListViewControllerC03getB3Url12tuner_epg_id10completionySi_yyctFy9Alamofire12DataResponseVyypGcfU_TA + 17
	9   Alamofire                           0x0000000109ae8c5b $s9Alamofire11DataRequestC8response5queue0D10Serializer17completionHandlerACXDSo012OS_dispatch_E0CSg_xyAA0B8ResponseVy16SerializedObjectQzGctAA0bkF8ProtocolRzlFyycfU_yycfU_ + 411
	10  Alamofire                           0x0000000109af1de8 $s9Alamofire11DataRequestC8response5queue0D10Serializer17completionHandlerACXDSo012OS_dispatch_E0CSg_xyAA0B8ResponseVy16SerializedObjectQzGctAA0bkF8ProtocolRzlFyycfU_yycfU_TA + 40
	11  Alamofire                           0x0000000109aa165d $sIeg_IeyB_TR + 45
	12  libdispatch.dylib                   0x000000010e5eed7f _dispatch_call_block_and_release + 12
	13  libdispatch.dylib                   0x000000010e5efdb5 _dispatch_client_callout + 8
	14  libdispatch.dylib                   0x000000010e5fd080 _dispatch_main_queue_callback_4CF + 1540
	15  CoreFoundation                      0x000000010d17da79 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
	16  CoreFoundation                      0x000000010d178126 __CFRunLoopRun + 2310
	17  CoreFoundation                      0x000000010d1774d2 CFRunLoopRunSpecific + 626
	18  GraphicsServices                    0x0000000111cfb2fe GSEventRunModal + 65
	19  UIKitCore                           0x0000000114712fc2 UIApplicationMain + 140
	20  m3u8                                0x0000000105b8562b main + 75
	21  libdyld.dylib                       0x000000010e664541 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)