rtt bugfix

        return sendStreamDataEarly(stream_id, data, len, fin);

    }

    if (_conn_state.load() != ConnectionState::Connected && !_handshake_complete) {

    // RFC 9001 §4.1.1: a server MAY send 1-RTT packets as soon as it has

    // sent its own Finished — it doesn't need to wait for (or verify) the

    // client's Finished first, i.e. _handshake_complete (which this server

    // only sets upon receiving the *client's* Finished) is stricter than

    // the RFC requires. Without this, a server that accepted 0-RTT could

    // decrypt a client's early data (processZeroRTTPacket() already derives

    // _app_keys by then, via processClientHello() -> sendServerHello() ->

    // sendServerHandshakeFlight()) but could never reply to it early,

    // defeating the entire point of accepting 0-RTT in the first place.

    bool server_app_keys_ready = _is_server && _app_keys.send.aes_gcm != nullptr;

    if (_conn_state.load() != ConnectionState::Connected && !_handshake_complete && !server_app_keys_ready) {

        return 0;

    }