Advanced protocols like SRP-6a perform authentication in several steps.
So passing credentials isn't enough for performing the authentication.
Zyan needs some extension points for multi-step authentication.

References:

• RFC2945 — SRP-6a protocol
• RFC5054 — SRP for TLS authentication
• SRP-6a design overview by Stanford University
• Reference SRP implementation by Stanford University
• secure-remote-password npm package