@Before
  public void setUp() {
    CALLED.set(0);
    BAD_RESP_INDEX = -1;
    GOOD_RESP_INDEXS = Collections.emptySet();
  }
A dummy RpcChannel implementation that intercepts the GetClusterId() RPC calls and injects
errors. All other RPCs are ignored.
hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestRpcBasedRegistryHedgedReads.java