Conversion trait to convert an Iterator to a ParallelIterator.

This creates a "bridge" from a sequential iterator to a parallel one, by distributing its items across the Rayon thread pool. This has the advantage of being able to parallelize just about anything, but the resulting ParallelIterator can be less efficient than if you started with par_iter instead. However, it can still be useful for iterators that are difficult to parallelize by other means, like channels or file or network I/O.

Iterator items are pulled by next() one at a time, synchronized from each thread that is ready for work, so this may become a bottleneck if the serial iterator can't keep up with the parallel demand. The items are not buffered by IterBridge, so it's fine to use this with large or even unbounded iterators.

The resulting iterator is not guaranteed to keep the order of the original iterator.

Examples

To use this trait, take an existing Iterator and call par_bridge on it. After that, you can use any of the ParallelIterator methods:

use rayon::iter::ParallelBridge;
use rayon::prelude::ParallelIterator;
use std::sync::mpsc::channel;

let rx = {
    let (tx, rx) = channel();

    tx.send("one!");
    tx.send("two!");
    tx.send("three!");

    rx
};

let mut output: Vec<&'static str> = rx.into_iter().par_bridge().collect();
output.sort_unstable();

assert_eq!(&*output, &["one!", "three!", "two!"]);