Function keep_primary_context 

fn keep_primary_context(device: CUdevice)

Hold one reference on device’s primary CUDA context for the life of the process, once a session on it has opened. A capture restarted while a game fills the GPU’s memory then retains the context it had instead of creating one, which can fail there and leave the stream on the CPU. The cost is the idle context’s 106 MiB of VRAM on a device that has encoded once, kept also while no session runs. Its own copy of the driver’s entry points keeps libcuda loaded after the last session’s copy goes.