void testTreeCache()
{
   
   // Open file
   auto f = TFile::Open("http://root.cern.ch/files/h1/dstarmb.root");

   // Get the tree
   auto t = (TTree *) f->Get("h42");

   // Check the cache
   Printf("(TFileCacheRead *) %p", f->GetCacheRead());

   // Set the cache
   t->SetCacheSize(30000000);

   // Use it
   t->Draw("aplan");

   // Check the cache
   Printf("(TFileCacheRead *) %p", f->GetCacheRead());

   // And its content
   if (f->GetCacheRead()) f->GetCacheRead()->Print();

   // Reset the cache
   t->SetCacheSize(0);

   // Check the cache
   Printf("(TFileCacheRead *) %p", f->GetCacheRead());
}