easylogging bench and fix async compare with g2log

bench/g2log-async.cpp

@@ -0,0 +1,57 @@
+#include <thread>
+#include <vector>
+#include <atomic>
+#include <iostream>
+#include <chrono>
+
+#include "g2logworker.h"
+#include "g2log.h"
+
+using namespace std;
+template<typename T> std::string format(const T& value);
+
+int main(int argc, char* argv[])
+{
+	using namespace std::chrono;
+	using clock=steady_clock;
+    int thread_count = 10;
+    
+    if(argc > 1)
+        thread_count = atoi(argv[1]);
+    int howmany = 1000000;
+
+    g2LogWorker g2log(argv[0], "logs");
+    g2::initializeLogging(&g2log);
+
+
+    std::atomic<int > msg_counter {0};
+    vector<thread> threads;
+	auto start = clock::now();
+    for (int t = 0; t < thread_count; ++t)
+    {
+        threads.push_back(std::thread([&]()
+        {
+            while (true)
+            {
+                int counter = ++msg_counter;
+                if (counter > howmany) break;
+                LOG(INFO) << "g2log message #" << counter << ": This is some text for your pleasure";
+            }
+        }));
+    }
+
+
+    for(auto &t:threads)
+    {
+        t.join();
+    };    	 
+    
+	duration<float> delta = clock::now() - start;
+	float deltaf = delta.count();
+    auto rate = howmany/deltaf;
+    
+    cout << "Total: " << howmany << std::endl;
+    cout << "Threads: " << thread_count << std::endl;
+    std::cout << "Delta = " << deltaf << " seconds" << std::endl;
+    std::cout << "Rate = " << rate << "/sec" << std::endl;
+}