code: func (b *BlockChain) IsCurrent() bool {
  	b.chainLock.RLock()
  	defer b.chainLock.RUnlock()
  
  	return b.isCurrent()
  }
docs: // IsCurrent returns whether or not the chain believes it is current.  Several
  // factors are used to guess, but the key factors that allow the chain to
  // believe it is current are:
  //  - Latest block height is after the latest checkpoint (if enabled)
  //  - Latest block has a timestamp newer than 24 hours ago
  //
  // This function is safe for concurrent access.