code: func (c *chainView) SetTip(node *blockNode) {
  	c.mtx.Lock()
  	c.setTip(node)
  	c.mtx.Unlock()
  }
docs: // SetTip sets the chain view to use the provided block node as the current tip
  // and ensures the view is consistent by populating it with the nodes obtained
  // by walking backwards all the way to genesis block as necessary.  Further
  // calls will only perform the minimum work needed, so switching between chain
  // tips is efficient.
  //
  // This function is safe for concurrent access.