Rust Binary Tree Implementation

I am developing this binary tree implementation with a few goals in mind.

1. I want to truly learn Rust
2. I want to use this code to solve Project Euler questions that require a Binary Tree
3. I want to learn how Rust handles Memory so that I can implement this in many different ways.

Current Approach

My current approach is to have the main Tree object own all the memory for the tree. As opposed to each parent owning it's children and using the Reference counter/Reference cell.

Again, I am doing this purely for my own education of the Rust library. Considering I could easily use the pre-built "graph-builder" crate to create a binary tree, this really only has educational purposes.