【网络通信】断线重连的消息补偿：掉线期间的增量补发

---服务端：每条下发消息携带递增序号
function ReliableSend(actor, msgType, payload)
    actor.seq = (actor.seq or 0) + 1
    sendmsg(actor, msgType, actor.seq .. ":" .. payload)
    pendingForSeq(actor, actor.seq, payload)
end

---重连触发：按客户端上报的序号补发增量
function playreconnection(actor, lastSeq)
    local buffered = actor.seqBuffer
    if lastSeq and buffered and lastSeq < actor.seq then
        local resend = 0
        for seq = lastSeq + 1, actor.seq do
            if buffered[seq] then
                sendmsg(actor, msgType, seq .. ":" .. buffered[seq])
                resend = resend + 1
            end
        end
        sendmsg(actor, 1, "已为玩家补同步掉线期间的 " .. resend .. " 条变化")
    end
end