【网络通信】消息优先级：战斗包与聊天包的分级通道

---网关发送队列：按优先级分档
local CH = {
    { q = {}, limit = 500, budget = 20 },  -- P0 战斗/移动
    { q = {}, limit = 300, budget = 60 },  -- P1 交互/物品
    { q = {}, limit = 200, budget = 200 }, -- P2 聊天/特效
}

function CH.push(conn, pkg, pri)
    local c = CH[pri] or CH[3]
    if #c.q >= c.limit then
        if pri >= 2 then return false end -- P2 满则丢弃
        table.remove(c.q, 1)              -- 高优挤掉最老包
    end
    c.q[#c.q + 1] = { conn = conn, pkg = pkg, at = os.clock() }
    return true
end

---每帧的发送调度：按预算逐档下发
function CH.drain()
    local frameStart = os.clock()
    for pri = 1, 3 do
        local c = CH[pri]
        while #c.q > 0 do
            local item = table.remove(c.q, 1)
            sendPkg(item.conn, item.pkg)
            if (os.clock() - frameStart) * 1000 >= c.budget then break end
        end
        if (os.clock() - frameStart) * 1000 >= c.budget then break end
    end
end