Returns the global RewardData struct for the staking contract.
/*** @notice Data structure containing information pertaining to a reward period* @dev All rewards are denominated in stTBY shares due to the token's rebasing nature* @param index The last index that the rewards were updated* @param lastShares The last shares balance of rewards available in the contract*/structRewardData {uint128 index;uint128 lastShares;}
/*** @notice Data structure containing information pertaining to a user's stake* @dev All rewards are denominated in stTBY shares due to the token's rebasing nature* @param amountStaked The amount of STAKEUP tokens currently staked* @param index The last index that the users rewards were updated* @param rewardsAccrued The amount of stTBY rewards that have accrued to the stake*/structStakingData {uint256 amountStaked;uint128 index;uint128 rewardsAccrued;}