func (c *ShardChain) Tip() (*index.ShardBlockNode, error) {
	c.lock.Lock()
	defer c.lock.Unlock()
	return c.tip()
}
// Tip gets the block node of the tip of the blockchain.
Tip gets the block node of the tip of the blockchain.
// Tip gets the block node of the tip of the blockchain .
func (c *ShardChain) Tip() (*index.ShardBlockNode, error) {
	c.lock.Lock()
	defer c.lock.Unlock()
	return c.tip()
}
func ( c * ShardChain ) Tip ( ) ( * index . ShardBlockNode , error ) { c . lock . Lock ( ) defer c . lock . Unlock ( ) return c . tip ( ) }
Tip gets the block node of the tip of the blockchain.
Tip gets the block node of the tip of the blockchain .