code: public AuthnStatement newAuthnStatement(final String contextClassRef, final ZonedDateTime authnInstant,
                                              final String sessionIndex) {
          LOGGER.trace("Building authentication statement with context class ref [{}] @ [{}] with index [{}]",
              contextClassRef, authnInstant, sessionIndex);
          val stmt = newSamlObject(AuthnStatement.class);
          val ctx = newSamlObject(AuthnContext.class);
  
          val classRef = newSamlObject(AuthnContextClassRef.class);
          classRef.setAuthnContextClassRef(contextClassRef);
  
          ctx.setAuthnContextClassRef(classRef);
          stmt.setAuthnContext(ctx);
          stmt.setAuthnInstant(DateTimeUtils.dateTimeOf(authnInstant));
          stmt.setSessionIndex(sessionIndex);
          return stmt;
      }
docs: New authn statement.
  
  @param contextClassRef the context class ref such as {@link AuthnContext#PASSWORD_AUTHN_CTX}
  @param authnInstant    the authn instant
  @param sessionIndex    the session index
  @return the authn statement