Tx broadcaster race condition on shutdown

[sug0]

There is a race condition in the tx broadcaster. It's possible to request the ledger to shut down, while the shell is still comitting. Meanwhile, the broadcaster receives a shutdown signal and aborts. If txs are queued in the commit, they won't actually be broadcasted because the broadcaster task has already been killed.

[cwgoes]

@sug0 is this still applicable?

[sug0]

I don't know, but afaik there has been no effort towards fixing this bug

[sug0]

#2598 indirectly patches up this problem, but doesn't necessarily fix it. this is because while the broadcaster will still be executing, it won't be receiving any txs to broadcast. at the time of this writing, only ethereum bridge protocol txs are sent by the broadcaster