CoreML Memory Leak in iOS 14.5

1. Whenever try handler.perform([visionRequest]) throws an error (Error Domain=com.apple.vis Code=11 "encountered unknown exception" UserInfo={NSLocalizedDescription=encountered unknown exception}), the pixelBuffer memory is held and never released, it made the buffers of AVCaptureOutput full then new frame not came.

2. I have to change the code as below, by copy the pixelBuffer to another var, I solved the problem that new frame not coming, but memory leak problem is still happened.

Code Block 
private func predictWithPixelBuffer(sampleBuffer: CMSampleBuffer) {
  guard let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else {
    return
  }
  
  // Get additional info from the camera.
  var options: [VNImageOption : Any] = [:]
  if let cameraIntrinsicMatrix = CMGetAttachment(sampleBuffer, kCMSampleBufferAttachmentKey_CameraIntrinsicMatrix, nil) {
    options[.cameraIntrinsics] = cameraIntrinsicMatrix
  }
  
  autoreleasepool {
    // Because of iOS 14.5, there is a bug that when perform vision request failed, pixel buffer memory leaked so the AVCaptureOutput buffers is full, it will not output new frame any more, this is a temporary work around to copy pixel buffer to a new buffer, this currently make the memory increased a lot also. Need to find a better way
    var clonePixelBuffer: CVPixelBuffer? = pixelBuffer.copy()
    let handler = VNImageRequestHandler(cvPixelBuffer: clonePixelBuffer!, orientation: orientation, options: options)
    print("[DEBUG] detecting...")
    
    do {
      try handler.perform([visionRequest])
    } catch {
      delegate?.detector(didOutputBoundingBox: [])
      failedCount += 1
      print("[DEBUG] detect failed \(failedCount)")
      print("Failed to perform Vision request: \(error)")
    }
    clonePixelBuffer = nil
  }
}