Use podio::Reader and podio::Writer with IOSvc

[jmcarcell]

BEGINRELEASENOTES

• Use podio::Reader and podio::Writer with IOSvc, so that it is easy to write TTrees or RNTuples by changing the IOType parameter given to IOSvc in the steering file.

ENDRELEASENOTES

[m-fila]

Is there a reason to dynamically allocate the writer and reader?

• They already are type erased
• getWriter() always return a valid object and is always assumed to do so
• I think the wrtier's finish method could be called directly instead triggering with pointer reset, no?

[m-fila]

podio::Writer allows also SIO. Is this intentional to exclude it?

[jmcarcell]

The demand for writing EDM4hep files using SIO is quite low. If someone wants it we can add it.

[tmadlener]

Could be nice for some testing at some point, but I agree we can easily toggle this once it becomes necessary.

[jmcarcell]

Now the Reader and Writer are stored in an std::optional and there isn't any dynamic allocation.

I think the wrtier's finish method could be called directly instead triggering with pointer reset, no?

We could but then the writer can't be used anymore so we may as well delete it, which prevents further usage of the writer possibly by mistake.

[tmadlener]

Should these be named differently now that they are no longer pointer backed? Something like resetWriter|resetReader?

[jmcarcell]

I think it doesn't matter but the reason why they are needed is because services in Gaudi are not deleted so making the connection would be easier in case one wants to look for the old issue where this is described in Gaudi and technically they are being deleted.