Profiling harness for palette expansion in `png` crate

main.rs

use std::fs::File;

fn main() {
    // loop 10 times to get lots of samples and a more clear profile
    for i in 0..10 {
        let filename = std::env::args_os().nth(1).expect("No input file provided");
        let mut decoder = png::Decoder::new(File::open(filename).unwrap());
        // Set the decoder to expand palletted images into RGBA instead of simply outputting palette indices
        // Without this the 
        decoder.set_transformations(png::Transformations::EXPAND);
        let mut reader = decoder.read_info().unwrap();
        // Allocate the output buffer.
        let mut buf = vec![0; reader.output_buffer_size()];
        // Read the next frame. An APNG might contain multiple frames.
        let _info = reader.next_frame(&mut buf).unwrap();
    }
}