pub unsafe extern "C" fn proj_operation_factory_context_set_area_of_interest(
    ctx: *mut PJ_CONTEXT,
    factory_ctx: *mut PJ_OPERATION_FACTORY_CONTEXT,
    west_lon_degree: f64,
    south_lat_degree: f64,
    east_lon_degree: f64,
    north_lat_degree: f64
)