You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mod.rs
    path of file: ./repos/cnosdb/query_server/query/src/extension/expr/window
    
    the code of the file until where you have to start completion: mod time_window;

use spi::query::function::FunctionMetadataManager;
use spi::Result;

pub fn register_window_udfs(func_manager: 
    
pub fn register_window_udfs(func_manager: &mut dyn FunctionMetadataManager) -> Result<()> {
    // extend function...
    // eg.
    //   example::register_udf(func_manager)?;
    time_window::register_udf(func_manager)?;
    Ok(())
}