refactor(Metrics): filter out "bad" metrics and allow normal ones to be sent (#2453)

src/gta/json_serializer.hpp

@@ -0,0 +1,36 @@
+#pragma once
+
+namespace rage
+{
+    #pragma pack(push, 1)
+    class json_serializer
+    {
+        uint32_t unk0;   // 0x00
+        uint32_t unk1;   // 0x00
+        char* buffer;    // 0x08
+        uint32_t curlen; // 0x10
+        uint32_t maxlen; // 0x14
+        uint32_t unk4;   // 0x18
+        uint8_t flags;   // 0x1C
+
+    public:
+        json_serializer(char* _buffer, uint32_t _length) :
+            buffer(_buffer),
+            maxlen(_length)
+        {
+            unk0
+                = 0;
+                unk1   = 0;
+                curlen = 0;
+                unk4   = 1;
+                flags  = 0;
+        }
+
+        inline char* get_string() const
+        {
+            return buffer;
+        }
+    };
+    static_assert(sizeof(json_serializer) == 0x1D); // size is actually 0x20
+    #pragma pack(pop)
+}