code: public OMVRBTreeEntryPersistent<K, V> delete() throws IOException {
      if (dataProvider != null) {
        pTree.removeNodeFromMemory(this);
        pTree.removeEntry(dataProvider.getIdentity());
  
        // EARLY LOAD LEFT AND DELETE IT RECURSIVELY
        if (getLeft() != null)
          ((OMVRBTreeEntryPersistent<K, V>) getLeft()).delete();
  
        // EARLY LOAD RIGHT AND DELETE IT RECURSIVELY
        if (getRight() != null)
          ((OMVRBTreeEntryPersistent<K, V>) getRight()).delete();
  
        // DELETE MYSELF
        dataProvider.removeIdentityChangedListener(this);
        dataProvider.delete();
        clear();
      }
  
      return this;
    }
docs: Delete all the nodes recursively. IF they are not loaded in memory, load all the tree.
  
  @throws IOException