code: func (h *blockHeaderStore) ChainTip() (*wire.BlockHeader, uint32, error) {
  	// Lock store for read.
  	h.mtx.RLock()
  	defer h.mtx.RUnlock()
  
  	_, tipHeight, err := h.chainTip()
  	if err != nil {
  		return nil, 0, err
  	}
  
  	latestHeader, err := h.readHeader(tipHeight)
  	if err != nil {
  		return nil, 0, err
  	}
  
  	return &latestHeader, tipHeight, nil
  }
docs: // ChainTip returns the best known block header and height for the
  // blockHeaderStore.
  //
  // NOTE: Part of the BlockHeaderStore interface.