[DRAFT] Add a null check for the lower level (de)serializer in ReleaseUnmanagedResources method during dispose flow of C# SerDe objects to avoid NPEs during disposal

[isaurab007]

Add a null check for the lower level (de)serializer in ReleaseUnmanagedResources method during dispose flow of C# SerDe objects

Issue #, if available:

Right now, the Dispose methods in GlueSchemaRegistryDeserializer and GlueSchemaRegistrySerializer which are called during Finalize flow (triggered during garbage collection) are not thread safe.

However, it needs to be thread-safe as per recommendation. Ref: https://stackoverflow.com/questions/5306860/should-idisposable-dispose-be-made-safe-to-call-multiple-times

Description of changes:

We are handling a specific exception during the dispose flow (NullReferenceException) by checking if the lower-level serializer or deserializer object is null.

Before the null-check

After the null-check

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.