code: func (c *Ctrie) Clear() {
  	for {
  		root := c.readRoot()
  		gen := &generation{}
  		newRoot := &iNode{
  			main: &mainNode{cNode: &cNode{array: make([]branch, 0), gen: gen}},
  			gen:  gen,
  		}
  		if c.rdcssRoot(root, gcasRead(root, c), newRoot) {
  			return
  		}
  	}
  }
docs: // Clear removes all keys from the Ctrie.