tset

    // holding it across the registry insertion below closes a race where

    // another thread could find this connection via the registry and

    // start touching its state before we've finished initializing it.

    auto child_ptr = std::make_shared<quic>();

    auto child_ptr = createChild();

    std::unique_lock<std::recursive_mutex> child_lock(child_ptr->quic_mtx());

    // Configure the new connection

    return {};

}

// ============================================================================

// Server accept(): factory for the child connection's dynamic type

// ============================================================================

// Base just makes a plain `quic`. libhttppp overrides this to return a

// libhttppp::Http3QuicSocket so accepted connections keep the virtual

// overrides above (buildAlpnExtension, sendControlStreams) instead of

// silently reverting to their no-op base versions.

std::shared_ptr<quic> quic::createChild() const {

    return std::make_shared<quic>();

}

// ============================================================================

// Socket Interface: sendData (Send application data)

// ============================================================================

		// extension sent). libhttppp overrides this with the real

		// implementation — see libhttppp::Http3QuicSocket.

		virtual std::vector<uint8_t> buildAlpnExtension(const std::string& alpn);

		// accept() calls this instead of `std::make_shared<quic>()` so an

		// accepted connection keeps the listener's own dynamic type (e.g.

		// libhttppp::Http3QuicSocket) — otherwise sendControlStreams()/

		// buildAlpnExtension() silently fall back to the no-op base

		// implementation on every accepted connection, since virtual

		// dispatch only helps once the object itself is the derived type.

		virtual std::shared_ptr<quic> createChild() const;

		void completeHandshake();

		// Packet number handling