private (bool, byte[]) GetVrfProof(BigInteger stake)
{
var seed = _systemContractReader.GetVrfSeed();
var rolls = stake / StakingContract.TokenUnitsInRoll;
var totalRolls = _systemContractReader.GetTotalStake().ToBigInteger() / StakingContract.TokenUnitsInRoll;
var(proof, value, j) = Vrf.Evaluate(_privateWallet.EcdsaKeyPair.PrivateKey.Buffer.ToByteArray(), seed,
StakingContract.Role, StakingContract.ExpectedValidatorsCount, rolls, totalRolls);
return(j > 0, proof);
}