mutex

local mutex = require('mutex')

local function ping_sender()
    sleep(30)
    scope(function()
        scope_cleanup_push(function() ws_write_mtx:unlock() end)
        ws_write_mtx:lock()
        ws:ping()
    end)
end

local function queue_consumer()
    scope(function()
        scope_cleanup_push(function() queue_mtx:unlock() end)
        queue_mtx:lock()
        while #queue == 0 do
            queue_cond:wait(queue_mtx)
        end
        for _, e in ipairs(queue) do
            consume_item(e)
        end
        queue = {}
    end)
end