The fastest way to read all tree branch data?

ROOT
3 
{
  TFile *f = TFile::Open("some_file.root");
  TTree *t; f->GetObject("some_tree", t);
  t->SetEstimate(-1); // keep all results (assumes one result per entry)
  Long64_t n = t->Draw("some_leaf", "", "goff");
#if 1 /* 0 or 1 */
  if (n > t->GetEstimate()) // just a precaution
    { t->SetEstimate(n); t->Draw("some_leaf", "", "goff"); }
#endif /* 0 or 1 */
  for (Long64_t i = 0; i < n; i++) std::cout << t->GetV1()[i] << std::endl;
}