How use libtooling rewriter to write new file？

Clang Frontend
,
1

i use libtooling rewriter change cpp code.

Rewriter.ReplaceText(range, ReplacementText);

then save change in original file

void ASTAnalyzeAction::EndSourceFileAction()
{
    Rewriter.overwriteChangedFiles();
}

i can change file in original cpp file，now，i want to write new file.how to write code?