static int handle_push_promise_frame(h2o_http2_conn_t *conn, h2o_http2_frame_t *frame, const char **err_desc)
{
    *err_desc = "received PUSH_PROMISE frame";
    return H2O_HTTP2_ERROR_PROTOCOL;
}
static int handle_push_promise_frame(h2o_http2_conn_t *conn, h2o_http2_frame_t *frame, const char **err_desc)
{
    *err_desc = "received PUSH_PROMISE frame";
    return H2O_HTTP2_ERROR_PROTOCOL;
}