fix bench queue size

bench/spdlog-bench-mt-async.cpp

@@ -17,7 +17,7 @@ int main(int argc, char* argv[])
     int howmany = 1000000;
 
     namespace spd = spdlog;
-    spd::set_async_mode(2500, std::chrono::seconds(0));
+    spd::set_async_mode(howmany, std::chrono::seconds(0));
     ///Create a file rotating logger with 5mb size max and 3 rotated files
     auto logger = spd::rotating_logger_mt("file_logger", "logs/spd-sample", 10 *1024 * 1024 , 5);
 
@@ -45,6 +45,5 @@ int main(int argc, char* argv[])
         t.join();
     };
 
-    spd::stop();
     return 0;
 }