code: func (c *chainView) genesis() *blockNode {
  	if len(c.nodes) == 0 {
  		return nil
  	}
  
  	return c.nodes[0]
  }
docs: // genesis returns the genesis block for the chain view.  This only differs from
  // the exported version in that it is up to the caller to ensure the lock is
  // held.
  //
  // This function MUST be called with the view mutex locked (for reads).