Added mdc.h

include/spdlog/mdc.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <map>
+
+namespace spdlog {
+    class mdc {
+    public:
+        using mdc_map_t = std::map<std::string, std::string>;
+
+        static void put(const std::string &key, const std::string &value) {
+            get_context()[key] = value;
+        }
+
+        static std::string get(const std::string &key) {
+            auto &context = get_context();
+            auto it = context.find(key);
+            if (it != context.end()) {
+                return it->second;
+            }
+            return "";
+        }
+
+        static void remove(const std::string &key) { get_context().erase(key); }
+
+        static void clear() { get_context().clear(); }
+
+        static mdc_map_t &get_context() {
+            static thread_local mdc_map_t context;
+            return context;
+        }
+    };
+
+}  // namespace spdlog