Till Rohrmann

The main part of the business logic of a SDK lives in the internal [state machine](https://github.com/restatedev/sdk-typescript/blob/e13df4b0441b3c1e2524c26905b2888165192ef3/packages/restate-sdk/src/state_machine.ts). The state machine is called from the [node enpoint](https://github.com/restatedev/sdk-typescript/blob/e13df4b0441b3c1e2524c26905b2888165192ef3/packages/restate-sdk/src/endpoint/node_endpoint.ts#L70) via the [GenericHandler](https://github.com/restatedev/sdk-typescript/blob/e13df4b0441b3c1e2524c26905b2888165192ef3/packages/restate-sdk/src/endpoint/handlers/generic.ts). The invocation...

I've rebased this PR onto the latest `main`. @rhubner is there anything else that I need to do before this PR can be merged?

I've rebased this PR onto the latest `main`. I think this extension of the C API could be useful for others as well. Right now our project relies on it...

@cbi42, @jaykorean could you maybe help with moving this PR forward? I've seen that you've been actively reviewing C API related PRs recently.

Thanks a lot for pointing the problem out to me @jaykorean. I think you are right that this was the cause for the leak. I've pushed an update.

@rhubner sure. I'll make sure to add the required test coverage and let you know once I'm done with it.

@rhubner, I've added tests for `rocksdb_writebatch_wi_create_iterator_with_base_readopts` and `rocksdb_writebatch_wi_create_iterator_with_base_cf_readopts`. Let me know whether this is sufficient.

@rhubner is there anything else needed before merging this PR?

@rhubner let me know if there is anything else missing for merging this PR.

I've rebased this PR onto the latest `main`. @rhubner are there other things missing? It would help us a lot to get this C API extension merged since our project...