Merge remote-tracking branch 'arthuredelstein/21873'

    but never attach a new stream to a circuit that is too old.  For hidden

    services, this applies to the __last__ time a circuit was used, not the

    first. Circuits with streams constructed with SOCKS authentication via

    SocksPorts that have **KeepAliveIsolateSOCKSAuth** ignore this value.

    SocksPorts that have **KeepAliveIsolateSOCKSAuth** also remain alive

    for MaxCircuitDirtiness seconds after carrying the last such stream.

    (Default: 10 minutes)

[[MaxClientCircuitsPending]] **MaxClientCircuitsPending** __NUM__::

        Don't share circuits with streams targeting a different

        destination address.

    **KeepAliveIsolateSOCKSAuth**;;

        If **IsolateSOCKSAuth** is enabled, keep alive circuits that have

        streams with SOCKS authentication set indefinitely.

        If **IsolateSOCKSAuth** is enabled, keep alive circuits while they have

        at least one stream with SOCKS authentication active. After such a circuit

        is idle for more than MaxCircuitDirtiness seconds, it can be closed.

    **SessionGroup=**__INT__;;

        If no other isolation rules would prevent it, allow streams

        on this port to share circuits with streams from every other