在HTTP处理程序中，当您知道内容不会更改时是否可以返回304？

public void ProcessRequest(HttpContext context)
{
    var cache = context.Response.Cache;
    cache.SetCacheability(HttpCacheability.Public);
    cache.SetExpires(DateTime.Now.Add(CACHE_DURATION));
    cache.SetMaxAge(CACHE_DURATION);
    cache.AppendCacheExtension(\"must-revalidate, proxy-revalidate\");

    byte[] buffer = ...
    context.Response.ContentType = \"image/png\";
    context.Response.OutputStream.Write(buffer, 0, buffer.Length);
}