pub unsafe extern fn cudnnGetConvolutionBackwardFilterWorkspaceSize(handle: cudnnHandle_t, srcDesc: cudnnTensorDescriptor_t, diffDesc: cudnnTensorDescriptor_t, convDesc: cudnnConvolutionDescriptor_t, gradDesc: cudnnFilterDescriptor_t, algo: cudnnConvolutionBwdFilterAlgo_t, sizeInBytes: *mut size_t) -> cudnnStatus_t