The Lane state tracks the latest (highest) voucher nonce used to merge the lane as well as the amount it has already redeemed.

Specifies which `Lane`s to be merged with what `Nonce` on channelUpdate.

Modular Verification method.

A voucher is sent by `From` to `To` off-chain in order to enable `To` to redeem payments on-chain in the future.

A given payment channel actor is established by From to enable off-chain microtransactions to To to be reconciled and tallied on chain.