title: Manipulating the V8 ast
body: <p>I intend to implement a js code coverage directly in the v8 code.
  My initial target is to add a simple print for every statement in the abstract syntax tree.
  I saw that there is an <code>AstVisitor</code> class , which allows you to traverse the AST.
  so my question is how can i add a statement to the AST after the statement the visitor is currently visiting? </p>