Based on the provided extracts, there is no explicit mention of an upper size limit on the contents of the

state

parameter passed to the

read

method in a Source implementation, or what is emitted in state messages during read. The

state

is treated as a black box by the Airbyte protocol and is modeled as a JSON blob. It is used to allow a Source to pick up where it left off and to checkpoint data replication. The Source can track state however makes most sense to it. The state for an actor is emitted as a complete black box and is wrapped in the

AirbyteStateMessage

. The contents of the

data

field is what is passed to the Source on start up. However, it's important to note that while there's no specified size limit in the extracts, practical limitations may be imposed by the specific data store or system you're working with. For more details, you can refer to the [Airbyte Protocol](https://docs.airbyte.com/understanding-airbyte/airbyte-protocol) documentation.

Hmm, I don't know enough to give you a confident answer yet. The information extracts provided do not mention the use of

pickle

for serialization of the

state

blob in the Python source connector CDK. However, they do mention that the

state

attribute helps the CDK figure out the current state of sync at any moment and that the setter typically deserializes state saved by CDK and initializes the internal state of the stream. The getter should serialize the internal state of the stream. Here is an example of how the

state

getter and setter are implemented:

python @property   def state(self) -> Mapping[str, Any]:    return {self.cursor_field: str(self._cursor_value)}      @state.setter   def state(self, value: Mapping[str, Any]):    self._cursor_value = value[self.cursor_field]

For more details, you might want to check the [Airbyte documentation](https://docs.airbyte.com/connector-development/cdk-python/incremental-stream).