style(core.*, health.lua): better code style and backend strategy

lua/Trans/util/init.lua

@@ -0,0 +1,16 @@
+local M = {}
+M.test_api_latency = function(urls)
+    urls = type(urls) == 'string' and { urls } or urls
+
+    local f = [[curl -s -o /dev/null -w '[%s]延迟: %%{time_total}s %s']]
+    local result = {}
+    for _, url in ipairs(urls) do
+        local cmd = string.format(f, url, url)
+        local res = vim.fn.system(cmd)
+        result[#result + 1] = res
+    end
+
+    vim.pretty_print(result)
+end
+
+return M