sync() and skim()

3.2.1 sync() and skim()

To protect against bespoke token implementations that can update the pair contract’s balance, and to more gracefully handle tokens whose total supply can be greater, DEX Raiden v1.1 has two bail-out functions: sync()and skim().

sync() functions as a recovery mechanism in the case that a token asynchronously deflates the balance of a pair. In this case, trades will receive sub-optimal rates, and if no liquidity provider is willing to rectify the situation, the pair is stuck. sync() exists to set the reserves of the contract to the current balances, providing a somewhat graceful recovery from this situation. skim() functions as a recovery mechanism in case enough tokens are sent to an pair to overflow the two uint112 storage slots for reserves, which could otherwise cause trades to fail. skim() allows a user to withdraw the difference between the current balance of the pair if that difference is greater than 0.