Unresponsive on FTP server drop out

[AliveDevil]

When a download transfer is in progress (multiple connections, segmented) the moment the FTP server fails (IP available, Port dead) the macOS app becomes unresponsive.

Spindump.txt

[AliveDevil]

threaddump-1709213262090.tdump.txt

[dkocher]

The thread dump shows that the main thread is waiting for all transfer threads to complete.

	at ch.cyberduck.core.threading.ExecutorServiceThreadPool.shutdown(ExecutorServiceThreadPool.java:50)
	at ch.cyberduck.core.worker.ConcurrentTransferWorker.shutdown(ConcurrentTransferWorker.java:183)
	at ch.cyberduck.core.worker.AbstractTransferWorker.cleanup(AbstractTransferWorker.java:548)
	at ch.cyberduck.core.worker.AbstractTransferWorker.cleanup(AbstractTransferWorker.java:53)
	at ch.cyberduck.core.threading.TransferWorkerBackgroundAction.cleanup(TransferWorkerBackgroundAction.java:67)
	at ch.cyberduck.core.threading.TransferCollectionBackgroundAction.cleanup(TransferCollectionBackgroundAction.java:90)
	at ch.cyberduck.ui.cocoa.controller.TransferController$8.cleanup(TransferController.java:624)

Regression from 238ac9c.

[dkocher]

Was previously fixed in fa618e5.