为什么要从包含awaits的方法中使用Task.FromResult<T>(T result)?

我在一个教程中碰到了下面的方法;

    private async Task<ClaimsIdentity> GetClaimsIdentity(string userName, string password)
    {
        if (string.IsNullOrEmpty(userName) || string.IsNullOrEmpty(password))
            return await Task.FromResult<ClaimsIdentity>(null);

        // get the user to verifty
        var userToVerify = await _userManager.FindByNameAsync(userName);

        if (userToVerify == null) return await Task.FromResult<ClaimsIdentity>(null);

        // check the credentials
        if (await _userManager.CheckPasswordAsync(userToVerify, password))
        {
            return await Task.FromResult(_jwtFactory.GenerateClaimsIdentity(userName, userToVerify.Id));
        }

        // Credentials are invalid, or account doesn't exist
        return await Task.FromResult<ClaimsIdentity>(null);
    }

作者总是使用 await Task.FromResult<ClaimsIdentity>(...)

    private async Task<ClaimsIdentity> GetClaimsIdentity(string userName, string password)
    {
        if (string.IsNullOrEmpty(userName) || string.IsNullOrEmpty(password))
            return null;

        // get the user to verifty
        var userToVerify = await _userManager.FindByNameAsync(userName);

        if (userToVerify == null) return null;

        // check the credentials
        if (await _userManager.CheckPasswordAsync(userToVerify, password))
        {
            return _jwtFactory.GenerateClaimsIdentity(userName, userToVerify.Id);
        }

        // Credentials are invalid, or account doesn't exist
        return null;
    }

都是编译的。这两种方法有什么区别(如果有的话)?有什么可以利用的吗 await Task.FromResult<ClaimsIdentity>(null) 以这种方式?