Function set_max_blocking_threads 

pub fn set_max_blocking_threads(threads: NonZeroUsize)

Set the maximum number of threads used by the backing thread pool.

Example

use blocking::unblock;
use std::fs::{read_dir, File};
use std::io::prelude::*;

blocking::set_max_blocking_threads(NonZeroUsize::new(100).unwrap());

let mut files = Vec::new();
for entry in read_dir("/path/to/large/directory").unwrap() {
    files.push(unblock(move || -> std::io::Result<String> {
        let mut contents = String::new();
        let mut file = File::open(entry?.path())?;
        file.read_to_string(&mut contents)?;
        Ok(contents)
    }));
}