func (c *Chain) Next(node *BlockNode) *BlockNode {
	c.lock.Lock()
	defer c.lock.Unlock()

	return c.next(node)
}
// Next gets the next node in the chain.
Next gets the next node in the chain.
// Next gets the next node in the chain .
func (c *Chain) Next(node *BlockNode) *BlockNode {
	c.lock.Lock()
	defer c.lock.Unlock()
	return c.next(node)
}
func ( c * Chain ) Next ( node * BlockNode ) * BlockNode { c . lock . Lock ( ) defer c . lock . Unlock ( ) return c . next ( node ) }
Next gets the next node in the chain.
Next gets the next node in the chain .