🔧 build: use to-be-close syntax add RAII style queue lock

framework/lualib/zeus/skynet/queue2.lua

@@ -0,0 +1,39 @@
+local skynet = require "skynet"
+local coroutine = coroutine
+local assert = assert
+local tinsert = table.insert
+local tremove = table.remove
+local setmetatable = setmetatable
+
+function skynet.queue2()
+    local current_thread
+    local ref = 0
+    local thread_queue = {}
+
+    local scope_lock = setmetatable({}, {
+        __close = function()
+            ref = ref - 1
+            if ref == 0 then
+                current_thread = tremove(thread_queue, 1)
+                if current_thread then
+                    skynet.wakeup(current_thread)
+                end
+            end
+        end,
+    })
+
+    return function()
+        local thread = coroutine.running()
+        if current_thread and current_thread ~= thread then
+            tinsert(thread_queue, thread)
+            skynet.wait()
+            assert(ref == 0) -- current_thread == thread
+        end
+        current_thread = thread
+
+        ref = ref + 1
+        return scope_lock
+    end
+end
+
+return skynet.queue2