private void changeLifeVersionForBlobId(String blobIdStr, short lifeVersion) {
    for (MockServer server : mockServerLayout.getMockServers()) {
      if (server.getBlobs().containsKey(blobIdStr)) {
        server.getBlobs().get(blobIdStr).lifeVersion = lifeVersion;
      }
    }
  }
Helper method to simulate errors from the servers. Only one node in the datacenter where the put happened will
return success. No matter what order the servers are contacted, as long as one of them returns success, the whole
operation should succeed.
@param dcWherePutHappened the datacenter where the put happened.
ambry-router/src/test/java/com/github/ambry/router/GetBlobOperationTest.java