@Parameters
  public static Collection<Object[]> parameters() {
    return Arrays.asList(new Object[] { BlockingRpcClient.class.getName() },
      new Object[] { NettyRpcClient.class.getName() });
  }
Tests the pluggable authentication framework with SASL using a contrived authentication system.
This tests holds a "user database" in memory as a hashmap. Clients provide their password in the
client Hadoop configuration. The servers validate this password via the "user database".
hbase-server/src/test/java/org/apache/hadoop/hbase/security/provider/CustomSaslAuthenticationProviderTestBase.java