See: https://github.com/libvips/build-win64-mxe/tree/zlib-ng-experiment

Benchmark.cs

namespace Benchmark
{
    using BenchmarkDotNet.Attributes;
    using NetVips;

    [Config(typeof(Config))]
    public class Benchmark
    {
        [Benchmark(Description = "NetVips", Baseline = true)]
        [Arguments("x.jpg", "x.png", 0)]
        [Arguments("x.jpg", "x.png", 1)]
        [Arguments("x.jpg", "x.png", 2)]
        [Arguments("x.jpg", "x.png", 3)]
        [Arguments("x.jpg", "x.png", 4)]
        [Arguments("x.jpg", "x.png", 5)]
        [Arguments("x.jpg", "x.png", 6)]
        [Arguments("x.jpg", "x.png", 7)]
        [Arguments("x.jpg", "x.png", 8)]
        [Arguments("x.jpg", "x.png", 9)]
        public void NetVips(string input, string output, int compression)
        {
            // input = https://commons.wikimedia.org/wiki/File:Stream_near_a_white_mountain_(Unsplash).jpg (4,000 x 5,000 pixels - 4.98 MB)
            var im = Image.NewFromFile(input, access: Enums.Access.Sequential);

            im.WriteToFile(output, new VOption
            {
                {"strip", true},
                {"compression", compression}
            });
        }
    }
}

zlib-ng.md

BenchmarkDotNet=v0.11.5, OS=Windows 10.0.18362
Intel Core i5-8600K CPU 3.60GHz (Coffee Lake), 1 CPU, 6 logical and 6 physical cores
.NET Core SDK=2.2.401
  [Host]     : .NET Core 2.2.6 (CoreCLR 4.6.27817.03, CoreFX 4.6.27818.02), 64bit RyuJIT
  Job-OCCHPR : .NET Core 2.2.6 (CoreCLR 4.6.27817.03, CoreFX 4.6.27818.02), 64bit RyuJIT

Toolchain=.NET Core 2.2.0  

Method	input	output	compression	Mean	Error	StdDev	Ratio
NetVips	x.jpg	x.png	0	863.6 ms	15.176 ms	16.868 ms	1.00
NetVips	x.jpg	x.png	1	1,082.4 ms	14.518 ms	12.870 ms	1.00
NetVips	x.jpg	x.png	2	1,553.4 ms	10.740 ms	10.046 ms	1.00
NetVips	x.jpg	x.png	3	1,849.4 ms	6.130 ms	5.119 ms	1.00
NetVips	x.jpg	x.png	4	1,788.3 ms	6.058 ms	5.370 ms	1.00
NetVips	x.jpg	x.png	5	2,196.3 ms	8.231 ms	7.699 ms	1.00
NetVips	x.jpg	x.png	6	3,307.7 ms	54.311 ms	50.803 ms	1.00
NetVips	x.jpg	x.png	7	6,455.8 ms	25.202 ms	23.574 ms	1.00
NetVips	x.jpg	x.png	8	12,437.0 ms	40.883 ms	38.242 ms	1.00
NetVips	x.jpg	x.png	9	13,759.6 ms	33.855 ms	31.668 ms	1.00

zlib.md

BenchmarkDotNet=v0.11.5, OS=Windows 10.0.18362
Intel Core i5-8600K CPU 3.60GHz (Coffee Lake), 1 CPU, 6 logical and 6 physical cores
.NET Core SDK=2.2.401
  [Host]     : .NET Core 2.2.6 (CoreCLR 4.6.27817.03, CoreFX 4.6.27818.02), 64bit RyuJIT
  Job-FMAPFI : .NET Core 2.2.6 (CoreCLR 4.6.27817.03, CoreFX 4.6.27818.02), 64bit RyuJIT

Toolchain=.NET Core 2.2.0  

Method	input	output	compression	Mean	Error	StdDev	Ratio
NetVips	x.jpg	x.png	0	915.9 ms	18.119 ms	20.140 ms	1.00
NetVips	x.jpg	x.png	1	1,617.2 ms	7.912 ms	6.607 ms	1.00
NetVips	x.jpg	x.png	2	1,742.9 ms	7.154 ms	6.692 ms	1.00
NetVips	x.jpg	x.png	3	2,249.9 ms	7.621 ms	7.129 ms	1.00
NetVips	x.jpg	x.png	4	2,606.6 ms	16.200 ms	15.154 ms	1.00
NetVips	x.jpg	x.png	5	3,453.1 ms	8.956 ms	7.479 ms	1.00
NetVips	x.jpg	x.png	6	5,728.7 ms	21.255 ms	18.842 ms	1.00
NetVips	x.jpg	x.png	7	7,525.6 ms	132.807 ms	110.900 ms	1.00
NetVips	x.jpg	x.png	8	15,225.9 ms	317.596 ms	401.658 ms	1.00
NetVips	x.jpg	x.png	9	16,940.5 ms	337.410 ms	331.381 ms	1.00