subbridge_listBridgeshows the bridge contract addresses and their subscription status. Sub-bridge saves the list of bridge contract addresses in a file. On reboot, sub-bridge reloads the bridge contract list from the file.
handleNonce. Unlike in-chain transactions, the sub-bridge can handle a higher nonce request before the lower ones.
_to, this requests a KLAY transfer to
_toaddress in the counterpart chain.
SC_VTRECOVERY_INTERVALmeans an interval how often the value transfer recovery is executed.