Return an adjusted path if we're emulating a "current working
        directory" for the server.

def _adjust_cwd(self, path):
        """
        Return an adjusted path if we're emulating a "current working
        directory" for the server.
        """
        path = b(path)
        if self._cwd is None:
            return path
        if len(path) and path[0:1] == b_slash:
            # absolute path
            return path
        if self._cwd == b_slash:
            return self._cwd + path
        return self._cwd + b_slash + path