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: encode.rs
    path of file: ./repos/summer-boot/summer-boot/src/http1
    
    the code of the file until where you have to start completion: use std::io::Write;
use std::pin::Pin;
use std::time::SystemTime;

us
    
fn max_bytes_to_read(buf_len: usize) -> usize {
    if buf_len < 6 {
        // 最小读取大小为6表示正文中的内容。其他五个字节是 1\r\n\r\n
        //其中 _ 是实际内容
        panic!("buffers of length {} are too small for this implementation. if this is a problem for you, please open an issue", buf_len);
    }

    let bytes_remaining_after_two_cr_lns = (buf_len - 4) as f64;

    // the maximum number of bytes that the hex representation of remaining bytes might take
    let max_bytes_of_hex_framing = bytes_remaining_after_two_cr_lns.log2() / 4f64;

    (bytes_remaining_after_two_cr_lns - max_bytes_of_hex_framing.ceil()) as usize
}