[BUG] NetworkConnection.SetMaxDelay() does nothing, ChannelBuffer.m_LastFlushTime is always zero!

Unity Engine
1

Problem: NetworkConnection.SetMaxDelay(float) has no effect because ChannelBuffer.m_LastFlushTime is never set. This means that the buffer is flushed every update instead of every maxDelay seconds.

Solution: Set m_LastFlushTime to Time.time inside the ChannelBuffer.SendInternalBuffer() method.

Code showing the issue (decompiled from UnityEngine.Networking.dll)

ChannelBuffer.cs

//This is the only place that m_LastFlushTime is referenced; it is never set besides in the constructor
public void CheckInternalBuffer()
{
    if (((Time.time - this.m_LastFlushTime) > this.maxDelay) && !this.m_CurrentPacket.IsEmpty())
    {
        this.SendInternalBuffer();
    }
    if ((Time.time - this.m_LastBufferedMessageCountTimer) > 1f)
    {
        this.lastBufferedPerSecond = this.numBufferedPerSecond;
        this.numBufferedPerSecond = 0;
        this.m_LastBufferedMessageCountTimer = Time.time;
    }
}

//This function should be setting m_LastFlushTime but it does not.
public bool SendInternalBuffer()
{
    NetworkDetailStats.IncrementStat(NetworkDetailStats.NetworkDirection.Outgoing, 0x1d, "msg", 1);
    if (!this.m_isReliable || (this.m_PendingPackets.Count <= 0))
    {
        return this.m_CurrentPacket.SendToTransport(this.m_hostId, this.m_connectionId, this.m_channelId);
    }
    while (this.m_PendingPackets.Count > 0)
    {
        ChannelPacket packet = this.m_PendingPackets[0];
        if (!packet.SendToTransport(this.m_hostId, this.m_connectionId, this.m_channelId))
        {
            break;
        }
        s_PendingPacketCount--;
        this.m_PendingPackets.RemoveAt(0);
        FreePacket(packet);
        if (this.m_isBroken && (this.m_PendingPackets.Count < (this.m_maxPendingPacketCount / 2)))
        {
            if (LogFilter.logWarn)
            {
                Debug.LogWarning("ChannelBuffer recovered from overflow but data was lost.");
            }
            this.m_isBroken = false;
        }
    }
    return true;
}

NetworkConnection.cs

internal void FlushInternalBuffer()
        {
            if (this.m_Channels != null)
            {
                foreach (ChannelBuffer buffer in this.m_Channels)
                {
                    buffer.CheckInternalBuffer();
                }
            }
        }

NetworkConnection.FlushInternalBuffer() is called every update on both client and server for each connection present.

I have verified this bug with the debugger. For all connections, on client or server, the m_LastFlushTime field is always 0f.

2

FYI that bug is fixed in 5.2

3

Good to know, thanks.