code: private List<ServerConnection> updateServerList() {
          final Map<Endpoint, ServerConnection> allServersByEndpoint = allServers
                  .stream()
                  .collect(toImmutableMap(ServerConnection::endpoint,
                                          Function.identity(),
                                          (l, r) -> l));
          return allServers = delegate
                  .endpoints()
                  .stream()
                  .map(endpoint -> {
                      ServerConnection connection = allServersByEndpoint.get(endpoint);
                      if (connection != null) {
                          return connection;
                      }
                      return new ServerConnection(endpoint, createEndpointHealthChecker(endpoint));
                  })
                  .collect(toImmutableList());
      }
docs: Update the servers this health checker client talks to.