Specifies the resynchronization limit.
This property is used to overcome the asynchronicity between client and server.
For HOTP server (HMAC-based one-time password, RFC 4226) Delta contains the maximum possible deviation of the client's counter value.
For TOTP server (Time-based one-time password, RFC 6238) Delta contains the maximum number of time steps the client can be "out of synch".
The default value is 0.