'Returns whether the underlying path is a socket.
@return: C{True} if it is a socket, C{False} otherwise
@rtype: L{bool}
@since: 11.1'

def isSocket(self):

    st = self._statinfo
    if (not st):
        self.restat(False)
        st = self._statinfo
        if (not st):
            return False
    return S_ISSOCK(st.st_mode)
