FastGetMethodVsGetMethod.cs

using System;
using System.Linq.Expressions;
using System.Reflection;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

namespace FastGetMethodBenchmark
{
    public class FastGetMethodVsGetMethod
    {
        [Benchmark]
        public MethodInfo FastGetMethod() 
        {
            return FastGetMethod(A, 0);
        }
    
        public static MethodInfo FastGetMethod<T, TResult>(Func<T, TResult> func, T a)
        {
            return func.Method;
        }

        [Benchmark(Baseline = true)]
        public MethodInfo GetMethod()
        {
            return GetMethod(() => B(0));
        }
    
        public static MethodInfo GetMethod(Expression<Action> method)
        {
            if (method == null)
                throw new ArgumentNullException(nameof(method));

            return ((MethodCallExpression)method.Body).Method;
        }
    
        public int A(int b)=>b;
        public int B(int b)=>b;
    }

    public class Program
    {
        public static void Main(string[] args)
        {
            var summary = BenchmarkRunner.Run<FastGetMethodVsGetMethod>();
        }
    }
}