搜索联想：输入联想的下拉列表

-- 错误：每敲一键全量刷新，输入卡、列表闪
input:onChanged(function(text)
    refreshAllMatches(text)
end)

local pending, timerAt = nil, 0
local function onChanged(text)
    pending = text
    timerAt = os.clock() + 0.3
end
local function onTick()
    if pending ~= nil and os.clock() >= timerAt then
        local matches = filterByPrefix(pending)
        refreshDropdown(matches)
        pending = nil
    end
end
local function onPick(word)
    input:setText(word)
    hideDropdown()
end