'Initializes a new RPC session.
Arguments:
client -- The SleekXMPP client associated with this session.
session_close_callback -- A callback called when the
session is closed.'

def __init__(self, client, session_close_callback):

    self._client = client
    self._session_close_callback = session_close_callback
    self._event = threading.Event()
    self._entries = {}
    self._callbacks = {}
    self._acls = {}
    self._lock = RLock()
