Tasks: GAE Flex, INVALID_ARGUMENT, "x-goog-request-params"

I am trying to create tasks from a flex application environment with the following code:

from google.cloud import tasks_v2beta2

def create_task(project= PROJECT_ID, queue= QUEUE, location= QLOCATION, payload= None):
    """Create a task for a given queue with an arbitrary payload."""

    # Create a client.
    client = tasks_v2beta2.CloudTasksClient()

    # Construct the request body.
    task = {
        'app_engine_http_request': {  # Specify the type of request.
            'http_method': 'POST',
            'relative_url': '/bootstrapper'
        }
    }
    if payload is not None:
        # The API expects a payload of type bytes.
        converted_payload = payload.encode()

        # Add the payload to the request.
        task['app_engine_http_request']['payload'] = converted_payload

    # Construct the fully qualified queue name.
    parent = client.queue_path(project, location, queue)

    # Use the client to build and send the task.
    response = client.create_task(parent, task)

    print('Created task {}'.format(response.name))
    return response

create_task(payload="foo")

Stack Trace from Error Reporting:

Traceback (most recent call last):
  File "/env/lib/python3.6/site-packages/google/api_core/grpc_helpers.py", line 54, in error_remapped_callable
    return callable_(*args, **kwargs)
  File "/env/lib/python3.6/site-packages/grpc/_channel.py", line 500, in __call__
    return _end_unary_response_blocking(state, call, False, None)
  File "/env/lib/python3.6/site-packages/grpc/_channel.py", line 434, in _end_unary_response_blocking
    raise _Rendezvous(state, None, None, deadline)
grpc._channel._Rendezvous: <_Rendezvous of RPC that terminated with (StatusCode.INVALID_ARGUMENT, "x-goog-request-params" header is either missing or misformatted. "x-goog-request-params" must contain "parent=projects/sample_id/locations/sample_location/queues/foo_queue")>

I looked up online and I found similar error being addressed in the Ruby Client Lib, I am not sure if the same bug exisits in python client library as well.

[thakursc1-zz]

I don’t exactly remember but app engine service id or name was added to the task body as follows: 'service':'foo'

[moshevi]

To the body itself? not the appEngineHttpRequest as header? or the appEngineRouting object as service?