If you have a proxy that is completely unable to make any sort of outward connections to the internet, there is still hope. Since the the proxy uses a different buffer format than the client, you cannot flush proxy buffers with another connected client. However, you can do the following:

1. temporarily shut down your regular personal proxy
2. MOVE your proxy's buffers to another machine that does have Internet connectivity.
3. temporarily start up a new personal proxy on that connected machine using those buffers, allowing it to fetch/flush as necessary.
4. after the connected machine has finished its network activity, shut down that personal proxy.
5. MOVE the connected proxy's buffer back onto your normal proxy machine.
6. restart your normal personal proxy.

Note that it is important that you MOVE your buffers between machines (or at least replace as you copy them). This is because there is no way to merge proxy buffers, so you want to be sure you do not accidentally end up with two non-empty in buffers, for example.

Additionally, it may be necessary to explicitly enable the "expertmode" on the connected proxy's ini file, so that you can specify buffer thresholds that exceed 1000 (since the connected proxy will not have any observable incoming block rate for it to "automatically" size the thresholds for you).