Get an object directly from plasma without going through object table.

    Precondition: plasma_prefetch(object_id) has been called before.

def plasma_get(object_id):
    """Get an object directly from plasma without going through object table.

    Precondition: plasma_prefetch(object_id) has been called before.
    """
    client = ray.worker.global_worker.plasma_client
    plasma_id = ray.pyarrow.plasma.ObjectID(object_id)
    while not client.contains(plasma_id):
        pass
    return client.get(plasma_id)