Simple HTTP server in Rust

I just finished an excellent Udemy course titled Learn Rust by Building Real Applications by Lyubomir Gavadinov. I really appreciate this way of introducing programming concepts and paradigms - while building an actual application, explaining the rationale behind the language's concepts and improving the code in an iterative fashion.

Now I have my HTTP server and I am trying to decide about the next steps:

• Using this code as a basis for a simple PoS blockchain node
• Improving this code by introducing concurrency