regession fix

    // csock. QUIC connections share the parent socket and are routed via

    // accept().

    csock = nullptr;

    flush_pending_app();  // don't drop already-scanned packets from this cycle

    return;  // New connection created — exit drain loop

    // Fall through to the next datagram in this batch instead of returning

    // here: recvBatchAddrViews() already pulled every datagram in the

    // current batch out of the kernel socket queue, so returning early

    // silently dropped any later datagram in the *same* batch -- most

    // importantly another concurrent client's own new-connection Initial

    // packet, which the kernel no longer has queued for a subsequent

    // select()/recv to find. This is why quic_concurrent_test failed

    // reproducibly even with just 2 simultaneous connections: whenever two

    // clients' Initial packets landed in the same recv batch, only the

    // first was ever processed. Every other early-exit in this loop already

    // uses `continue` for exactly this reason; this was the one outlier.

    // flush_pending_app() still only runs once, at the end of the full

    // batch below, so packets for existing connections keep batching

    // together instead of flushing prematurely on every new connection.

    } // end msg_i loop