Add DebugConflictSet, which asserts using skip list as a reference

CC #23

ConflictSet.cpp

@@ -2510,6 +2510,10 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
   }
 
   explicit Impl(int64_t oldestVersion) : oldestVersion(oldestVersion) {
+#if DEBUG_VERBOSE
+    fprintf(stderr, "radix_tree: create\n");
+#endif
+
     // Insert ""
     root = allocators.node0.allocate(0);
     root->numChildren = 0;
@@ -2524,7 +2528,12 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
     root->entry.pointVersion = oldestVersion;
     root->entry.rangeVersion = oldestVersion;
   }
-  ~Impl() { destroyTree(root); }
+  ~Impl() {
+#if DEBUG_VERBOSE
+    fprintf(stderr, "radix_tree: destroy\n");
+#endif
+    destroyTree(root);
+  }
 
   NodeAllocators allocators;
 
@@ -3005,6 +3014,7 @@ void removeKey(Node *n) {
 
 struct __attribute__((visibility("default"))) PeakPrinter {
   ~PeakPrinter() {
+    printf("--- radix_tree ---\n");
     printf("malloc bytes: %g\n", double(mallocBytes));
     printf("Peak malloc bytes: %g\n", double(peakMallocBytes));
     printf("Node bytes: %g\n", double(nodeBytes));