Is your feature request related to a problem? Please describe.
The current implementation of PostgreSQLOnlineStoreConfig.online_write_batch() is quite slow.

Describe the solution you'd like
One of the suggested options discussed in this issue is using bulk writes with adbc.

Describe alternatives you've considered
Another option could be to use COPY FROM command. This performance benchmark shows that the number of rows written per second is significantly larger compared to the batch insert we are doing now.

This image shows the comparison from the performance benchmark:

Additional context
I think we should benchmark both solutions and pick the one that achieves the best performance.