- claimRedeemed(redeemedClaim: claim)
 - let openingCommitmentsHash = hash(state.parameters.openingCommitments)
 - assert self.successfulOpenings[openingCommitmentsHash] - checks whether the
   channel was successfully opened
 - if so, add to the withdrawal progress:
     self.openingClaimsInProgress[openingCommitmentsHash].redeemedCoins +=
     claim.end - claim.start
 - let claimInProgress = self.openingClaimsInProgress[openingCommitmentsHash]
 - if claimInProgress.redeemedCoins == claimInProgress.totalCoins,
   then forward the totalCoins to the state.parameters.onChainChannel(state.parameters.callData) - the opening has been fully claimed and the on-chain channel may take over.
 - Otherwise, not all money in the channel has been redeemed from the plasma contract yet,
   so we must wait.