Track session states

[sergiyvamz]

Summary

• track session states
• allow user to provide custom function to handle session state transfers

Description

Additional Reviewers

@karenc-bq
@davecramer
@hsuamz

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[scott-long-adp]

thanks for this -- we will be using ConnectionProviderManager.setConnectionInitFunc() from #705 to initialize new connections that were not able to go through PoolBase.setupConnection()

Regarding SessionStateTransferCallable, RestoreSessionStateCallable -

The default behavior for SessionStateTransferCallable is to propagate all properties from one connection to the other, including transaction isolation -- so this new default behavior may actually be sufficient.

But the default behavior for RestoreSessionStateCallable is only to restore a locally-saved readonly and autocommit property.

What is the reason for the limited number of properties restored by RestoreSessionStateCallable compared to SessionStateTransferCallable? Should we consider a RestoreSessionStateCallable event similar to ConnectionProviderManager.setConnectionInitFunc() and just reset all properties from the ground up?

thanks for any insight