如何在WebAPI2的IHttpActionResult中添加头部？

public class CustomActionResult : IHttpActionResult
{
    private readonly IHttpActionResult _innerResult;
    private readonly Dictionary<string, string> _headers;

    public CustomActionResult(IHttpActionResult innerResult, Dictionary<string, string> headers)
    {
        _innerResult = innerResult;
        _headers = headers;
    }

    public async Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        var response = await _innerResult.ExecuteAsync(cancellationToken);

        foreach (var header in _headers)
        {
            response.Headers.Add(header.Key, header.Value);
        }

        return response;
    }
}

public IHttpActionResult Get()
{
    var headers = new Dictionary<string, string>
    {
        { "CustomHeader1", "Value1" },
        { "CustomHeader2", "Value2" }
    };

    var innerResult = Ok("Hello, World!");
    var customResult = new CustomActionResult(innerResult, headers);

    return customResult;
}