// NoDelay, interval, window size are the most important configurations.
// let's force require the parameters so we don't forget it anywhere.
protected void SetupKcp(bool noDelay, uint interval = Kcp.INTERVAL, int fastResend = 0, bool congestionWindow = true, uint sendWindowSize = Kcp.WND_SND, uint receiveWindowSize = Kcp.WND_RCV)
{
// set up kcp over reliable channel (that's what kcp is for)
kcp = new Kcp(0, RawSendReliable);
// set nodelay.
// note that kcp uses 'nocwnd' internally so we negate the parameter
kcp.SetNoDelay(noDelay ? 1u : 0u, interval, fastResend, !congestionWindow);
kcp.SetWindowSize(sendWindowSize, receiveWindowSize);
// IMPORTANT: high level needs to add 1 channel byte to each raw
// message. so while Kcp.MTU_DEF is perfect, we actually need to
// tell kcp to use MTU-1 so we can still put the header into the
// message afterwards.
kcp.SetMtu(Kcp.MTU_DEF - CHANNEL_HEADER_SIZE);
state = KcpState.Connected;
refTime.Start();
}