Function igraph_residual_graph 

pub unsafe extern "C" fn igraph_residual_graph(
    graph: *const igraph_t,
    capacity: *const igraph_vector_t,
    residual: *mut igraph_t,
    residual_capacity: *mut igraph_vector_t,
    flow: *const igraph_vector_t,
) -> igraph_error_t