def start_stream(file_path, stream_name=None, private=False, username=''):
    """
    Uses the `/stream/start` endpoint taking the username as a parameter.
    If you specify no username, it will fallback to the default
    `KICKFLIP_USER_NAME` set in the set_aws_keys() function.

    e.g. username="banana1"

    """
    endpoint = KICKFLIP_API_URL + '/stream/start/'
    payload = {'username': KICKFLIP_USER_NAME}

    if username:
        payload['username'] = username

    user_response = kickflip_session.post(endpoint, payload)

    import pdb
    pdb.set_trace()
    stream_video(file_path)
    return ''