def stat(self):
return SFTP_OP_UNSUPPORTED<EOL>
Return an L{SFTPAttributes} object referring to this open file, or an
error code.  This is equivalent to L{SFTPServerInterface.stat}, except
it's called on an open file instead of a path.

@return: an attributes object for the given file, or an SFTP error
    code (like L{SFTP_PERMISSION_DENIED}).
@rtype: L{SFTPAttributes} I{or error code}