Lua漏桶：匀速流出的速率整形

local function drain(bucket, rate)
    local out = math.min(bucket.water, rate)
    bucket.water = bucket.water - out
    return out
end

local function pour(bucket, n, cap)
    bucket.water = math.min(bucket.water + n, cap)
    if bucket.water >= cap then
        return false   -- 桶满拒绝新请求
    end
    return true
end
local p = getplayerbyname("leak01")
local bucket = {water = 0}
local ok = pour(bucket, 500, 100)
sendmsg(p, 1, "入桶 " .. tostring(ok)
    .. "，积压 " .. bucket.water)