public Pair<SaslClientAuthenticationProvider, Token<? extends TokenIdentifier>>
    getSimpleProvider() {
    Optional<SaslClientAuthenticationProvider> optional = providers.stream()
      .filter((p) -> p instanceof SimpleSaslClientAuthenticationProvider).findFirst();
    return new Pair<>(optional.get(), null);
  }
Returns the provider and token pair for SIMPLE authentication. This method is a "hack" while
SIMPLE authentication for HBase does not flow through the SASL codepath.
hbase-client/src/main/java/org/apache/hadoop/hbase/security/provider/SaslClientAuthenticationProviders.java