How do I pass the input of a blob triggered starter function to activity functions within the orchestrator for Azure Durable Functions?

As the title says I have a starter function that is blob triggered and I’m looking to send the blob that triggered the starter through to the activity functions as an input. I have the option to pass in an input using the .start_new() method however these inputs must be JSON serializable which the blob file (func.InputStream) is not.

I have tried to decode the InputStream object (myblob) which allows me to pass it as an input but I lose some of the basic functionality I would have when it’s an InputStream object and also need to ensure I’m able to pass it into the subsquent cognitive services that will be called in the activity functions. See below for code of the starter function.

Starter Function

functions.json
`

{
  "scriptFile": "__init__.py",
  "bindings": [
    {
      "name": "myblob",
      "type": "blobTrigger",
      "direction": "in",
      "path": "container/{name}",
      "connection": "conn str"
    },
    {
      "name": "$return",
      "type": "blob",
      "path": "container/{name}",
      "connection": "AzureWebJobsStorage",
      "direction": "out"
    },
    {
      "name": "starter",
      "type": "durableClient",
      "direction": "in"
    }
  ]
}

`
init.py

async def main(myblob: func.InputStream, starter: str) -> func.InputStream:
    logging.info(f"Python blob trigger function processed blob n"
                 f"Name: {myblob.name}n"
                 f"Blob Size: {myblob.length} bytesnn")        
    client = df.DurableOrchestrationClient(starter)
    instance_id = await client.start_new('Orchestrator', client_input=myblob) ##Client_input must be json serializable
    logging.info(f"Started orchestration with ID = '{instance_id}'.")
    return myblob

Which Returns:
Exception: TypeError: class <class ‘azure.functions.blob.InputStream’> does not expose a to_json function