void MiningSetDifficulty(JObject obj)
{
//{"params": [32], "id": null, "method": "mining.set_difficulty"}
double difficulty = (double)obj["params"][0];
//difficulty = 32;
mLog.WriteLine("Set Difficulty: " + difficulty);
ulong baseDiff = 0x00000000FFFF0000;
double diff = (double)baseDiff;
// if scrypt
if( mClientManager.mMiningTarget.mPOWAlgorithm == HashAlgorithm.Scrypt )
diff *= 65536;
mServerDiff = (ulong)(diff / difficulty);
}