Easing curve benchmark (ppy/osu-framework#3026)

EasingBenchmark.cs

using System.Linq;
using BenchmarkDotNet.Attributes;
using osu.Framework.Graphics;
using osu.Framework.MathUtils;

namespace osu.Framework.Tests
{
    public class EasingBenchmark
    {
        [Params(Easing.InExpo, Easing.InElastic, Easing.OutElasticHalf, Easing.OutElasticQuarter, Easing.InOutElastic)]
        public Easing Easing { get; set; }

        private double[] args;

        [GlobalSetup]
        public void Setup()
        {
            args = Enumerable.Range(1, 1000)
                             .Select(arg => arg / 1000.0)
                             .ToArray();
        }

        [Benchmark]
        public double[] ApplyEasing() => args.Select(arg => Interpolation.ApplyEasing(Easing, arg)).ToArray();
    }
}