springrts.com widget to show frames which consumed a lot of time

lagtest.lua

function widget:GetInfo()
  return {
    name      = "LAG INFO",
    desc      = "abcdef",
    author    = "abcdef",
    date      = "abcdef",
    license   = "abcdef",
    layer     = 0,
    enabled   = true, --  loaded by default?
  }
end
local last = Spring.GetTimer()
function widget:GameFrame(frame)
        local cur = Spring.GetTimer()
        diff = Spring.DiffTimers(cur, last, true)
        last = cur
        if diff > 100 then
                Spring.Echo("GameFrame() delay: "..tostring(diff))
        end
end