🚀 go-pugleaf

Im implementing a big binary tree.  It can grow up a lot (several
MBytes),  then I have to save temporal files and merge them later.

To know when I have to save a binary tree to disk, I must find out what
is the size of the information (the object into the nodes).  I need
something like a C sizeOf.

Im trying to implement a sizeOf using java.lang.reflect.field, but I
dont know how to get a field from an object:

Object obj;
Field[] fields = obj.getClass().getDeclaredFields();

How can I get a field (fields[i]) from an object (obj)?

If anybody knows how can I implement a sizeOf.  I will apreciate yor
help.

Tanks.