Swap

Swap logic for Stake Exchange AMM follows two unique paths:

1. Instant Withdrawals: LST -> Native Token swaps for a dynamic fee.

2. New Stake: Native Token -> LST swaps the true rate with no fee.

   This 'swap' gives the same rate as `minting` the LST through the native LST protocol's contracts.

Instant Withdrawals for a fee are where LPs earn swap APY. New Stake swaps replace LST : Native Token at the true rate, rebalancing the pool without loss. STEX AMM only enters the LST Withdrawal Queue when more Instant Withdrawals than New Stake leaves the pool out of balance.