如何从Roslyn的另一个方法中作为参数传递的方法中获取返回类型？

using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;

public class ReturnTypeVisitor : CSharpSyntaxWalker
{
    private readonly SemanticModel _semanticModel;
    public ITypeSymbol ReturnType { get; private set; }

    public ReturnTypeVisitor(SemanticModel semanticModel)
    {
        _semanticModel = semanticModel;
    }

    public override void VisitInvocationExpression(InvocationExpressionSyntax node)
    {
        var symbolInfo = _semanticModel.GetSymbolInfo(node);
        if (symbolInfo.Symbol is IMethodSymbol methodSymbol)
        {
            ReturnType = methodSymbol.ReturnType;
        }

        base.VisitInvocationExpression(node);
    }
}

public class Program
{
    public static void Main()
    {
        string code = @"
            using System;

            public class MyClass
            {
                public int MyMethod()
                {
                    return 42;
                }

                public void AnotherMethod(Func<int> method)
                {
                    int result = method();
                    Console.WriteLine(result);
                }

                public void CallerMethod()
                {
                    AnotherMethod(MyMethod);
                }
            }
        ";

        SyntaxTree syntaxTree = CSharpSyntaxTree.ParseText(code);
        var compilation = CSharpCompilation.Create("MyCompilation", syntaxTrees: new[] { syntaxTree });

        SemanticModel semanticModel = compilation.GetSemanticModel(syntaxTree);
        var root = syntaxTree.GetRoot();

        var methodDeclaration = root.DescendantNodes().OfType<MethodDeclarationSyntax>()
            .Single(md => md.Identifier.ValueText == "CallerMethod");

        var returnTypeVisitor = new ReturnTypeVisitor(semanticModel);
        returnTypeVisitor.Visit(methodDeclaration);

        var returnType = returnTypeVisitor.ReturnType;
        Console.WriteLine(returnType);
    }
}