hasSufficientBalance method
Whether selectUTXOsForAmount can cover requiredAmount:
WalletState.availableBalance, the total of the UTXOs it may select,
is at least requiredAmount. Fees are the caller's to add.
Implementation
bool hasSufficientBalance(WalletState state, BigInt requiredAmount) {
return state.availableBalance >= requiredAmount;
}