code: protected void checkHealth(long threshold, NodeHealthChecker healthChecker) {
          final int state = this.state;
          if (anyAreSet(state, REMOVED | ACTIVE_PING)) {
              return;
          }
          healthCheckPing(threshold, healthChecker);
      }
docs: Check the health of the node and try to ping it if necessary.
  
  @param threshold     the threshold after which the node should be removed
  @param healthChecker the node health checker