如何在IdentityServer4 (asp.net核心)的token验证阶段获取原始请求头？

using IdentityServer4.Extensions;
using IdentityServer4.Models;
using IdentityServer4.Services;
using Microsoft.AspNetCore.Http;
using System.Collections.Generic;
using System.Security.Claims;
using System.Threading.Tasks;

public class CustomProfileService : IProfileService
{
    private readonly IHttpContextAccessor _httpContextAccessor;

    public CustomProfileService(IHttpContextAccessor httpContextAccessor)
    {
        _httpContextAccessor = httpContextAccessor;
    }

    public async Task GetProfileDataAsync(ProfileDataRequestContext context)
    {
        // 获取原始请求头
        var headers = _httpContextAccessor.HttpContext.Request.Headers;

        // 将原始请求头添加到用户的Claims中
        var claims = new List<Claim>();
        foreach (var header in headers)
        {
            claims.Add(new Claim(header.Key, header.Value));
        }

        context.IssuedClaims.AddRange(claims);
    }

    public async Task IsActiveAsync(IsActiveContext context)
    {
        context.IsActive = true;
    }
}

services.AddTransient<IProfileService, CustomProfileService>();