StaFi is a DeFi agreement that unlocks the liquidity of pledged assets. Users can place bets on PoS tokens through StaFi and receive rToken as a reward. While receiving the pledge reward, they can also engage in transactions. rFIS is a bet asset exchange certificate issued by StaFi to users. When a user pledges FIS (the original token of StaFi), StaFi will calculate the number of rFIS obtained by the user according to the exchange rate between the current FIS and rFIS. When a user holds rFIS, StaFi will calculate the user's redeemable FIS amount based on the deposit income of the FIS....