Added thread callback option to thread_pool

include/spdlog/async.h

@@ -18,8 +18,10 @@
 #include "spdlog/details/registry.h"
 #include "spdlog/details/thread_pool.h"
 
+
 #include <memory>
 #include <mutex>
+#include <functional>
 
 namespace spdlog {
 
@@ -70,12 +72,18 @@ inline std::shared_ptr<spdlog::logger> create_async_nb(std::string logger_name,
 }
 
 // set global thread pool.
-inline void init_thread_pool(size_t q_size, size_t thread_count)
+inline void init_thread_pool(size_t q_size, size_t thread_count, std::function<void()> on_thread_start)
 {
-    auto tp = std::make_shared<details::thread_pool>(q_size, thread_count);
+    auto tp = std::make_shared<details::thread_pool>(q_size, thread_count, on_thread_start);
     details::registry::instance().set_tp(std::move(tp));
 }
 
+// set global thread pool.
+inline void init_thread_pool(size_t q_size, size_t thread_count)
+{
+    init_thread_pool(q_size, thread_count, []{});
+}
+
 // get the global thread pool.
 inline std::shared_ptr<spdlog::details::thread_pool> thread_pool()
 {