Epic: Relayers should be able to accept payments for multi-hop messages

[nambrot]

Applications may need to send multi-hop messages, i.e. a return messages that allows the msg.sender to act upon success or failure of remote action (i.e. return collateral if a swap failed). Relayer's IGP's currently only quote for delivery of a single message, they are not expressive enough to account for multiple messages.

Alternatives

Wormhole

• Supports the forwarding of funds to the derivative message https://docs.wormhole.com/wormhole/quick-start/tutorials/hello-wormhole/beyond-hello-wormhole#feature-forwarding-going-from-chain-a-chain-b-chain-c

Axelar

• The relayer can track derivative messages automatically and apply them to the next message https://docs.axelar.dev/dev/general-message-passing/gas-services/pay-gas#two-way-call

Tasks

Beta Give feedback

1. https://github.com/hyperlane-xyz/issues/issues/597

[yorhodes]

I think the making the IGP contract ERC20 compatible will get us this much easier via hooks

[avious00]

also see #3661