the io_service run/run_once/poll should be called in a try-catch_all block in thread function in thread pools

the io_service->run should be guarded by a try catch(...) and exceptions should be logged (if possible):

void
IoServiceThreadPool::threadWork() {
    bool done = false;
    while (!done) {
        switch (getState()) {
        case State::RUNNING: {
            {
                std::unique_lock<std::mutex> lck(mutex_);
                running_++;

                // If We're all running notify main thread.
                if (running_ == pool_size_) {
                    main_cv_.notify_all();
                }
            }
            // try {                                   <<<---
            // Run the IOService.
            io_service_->run();
            // } catch(exception& ex) {                <<<---
            // LOG the exception error here            <<<---
            // } catch (...) {                         <<<---
            // LOG general error here                  <<<---
            // }                                       <<<---