[llvm] [llvm]Add a simple Telemetry framework (PR #102323)

[Vy Nguyen via llvm-commits]

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@@ -27,14 +27,14 @@ namespace telemetry {
 
 class Serializer {
 public:
-  virtual llvm::Error init() = 0;
+  virtual Error init() = 0;
   virtual void write(StringRef KeyName, bool Value) = 0;
   virtual void write(StringRef KeyName, int Value) = 0;
-  virtual void write(StringRef KeyName, size_t Value) = 0;
+  virtual void write(StringRef KeyName, unsigned long long Value) = 0;
   virtual void write(StringRef KeyName, StringRef Value) = 0;
   virtual void write(StringRef KeyName,
                      const std::map<std::string, std::string> &Value) = 0;
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oontvoo wrote:

So far, the only usage for this map is in LLDB and we only ever need `<string, string>`. 

the `startObject`, `endObject` approach seems fine .

https://github.com/llvm/llvm-project/pull/102323