Rust SHA-256 checksum

Question

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I'm relatively new to Rust and have implemented a function to calculate the checksum (SHA-256) of a PDF file. The function works fine for smaller files, but I've noticed a significant increase in execution time for larger files (e.g., 250MB).

Here's the current implementation:

use sha256::try_digest;
use std::id::Error;

fn file_checksum_sha_256(file_path: &str) -> Result<String, Error> {
    let file_path = Path::new(file_path);
    let file_checksum = try_digest(file_path);

    match file_checksum {
        Ok(cs) => Ok(cs),
        Err(err) => {
            eprintln!("Error generating file checksum: {}", err);
            Err(err)
        }
    }
}

When I ran my application with a 250MB PDF file, the execution time was around 13.27 seconds.

time ./MYAPP

real    13.27s
user    13.09s
sys     0.15s
cpu     99%

However, when I used the sha256sum Linux binary on the same file, it took only 1.16 seconds.

time sha256sum MYPDf.pdf
c47d0636584ddc5e28bb55fa9ea7498e58c88fa7af1773df63eb11d54bbe9d43  MYPDF.pdf

real    1.16s
user    1.13s
sys     0.03s
cpu     99%

My questions are:

1. Is the performance issue in my Rust code, or is this a normal behavior?
2. Could this be related to Rust itself, or is it more about the specific implementation?
3. Would introducing multi-threading in my Rust code potentially address this performance gap?

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