Update MC header when using event pool generator

Author: jackal1-66

Generators/include/Generators/GeneratorFromFile.h

@@ -87,11 +87,11 @@ class GeneratorFromO2Kine : public o2::eventgen::Generator
   void SetStartEvent(int start);
 
   void setContinueMode(bool val) { mContinueMode = val; };
-
- private:
   /** methods that can be overridden **/
   void updateHeader(o2::dataformats::MCEventHeader* eventHeader) override;
 
+ private:
+
   TFile* mEventFile = nullptr;     //! the file containing the persistent events
   TBranch* mEventBranch = nullptr; //! the branch containing the persistent events
   TBranch* mMCHeaderBranch = nullptr; //! branch containing MC event headers
@@ -143,6 +143,11 @@ class GeneratorFromEventPool : public o2::eventgen::Generator
     return import_good;
   }
 
+  void updateHeader(o2::dataformats::MCEventHeader* eventHeader) override
+  {
+    mO2KineGenerator->updateHeader(eventHeader);
+  }
+
   // determine the collection of available files
   std::vector<std::string> setupFileUniverse(std::string const& path) const;