Fix blocking send in online Histo sender

algo/base/HistogramSender.h

@@ -52,7 +52,8 @@ namespace cbm::algo
 
       zmq::message_t msg(serial_str.size());
       std::copy_n(static_cast<const char*>(serial_str.data()), msg.size(), static_cast<char*>(msg.data()));
-      fZmqSocket.send(msg, flags);
+      /// FIXME: read return value to catch EAGAIN indicating a failed emission, use it outside to skip histo reset
+      fZmqSocket.send(msg, flags | zmq::send_flags::dontwait);
     }
 
    private: