Bi-directional communication #18
Description
Real withdraw does not just return funds after request, it sends a message to the destination chain, 2 weeks later receives confirmation and only then transfers requested funds back to user, so we need messages in both directions. Need to support it on both chains.
Do we need messages to confirm that funds were deposited on the destination chain?
How does message structure change? Add "status" field?
For example, withdraw: sent_to_dst, received_on_dst, approved_on_dst, withdrawn.
I think there should be "finalized" status, for messages that we have nothing to do with and will never have again. And latestFinalizedIdx, to check withdraw messages from latestFinalizedIdx to latest.
Maybe store withdraws it a separate array?