Blocking vs Non-blocking file I/O

Blocking code is available in [blockin.rs](./src/blocking.rs] and non-blocking in async-tokio.rs.

Both programs read their respective source files and print it to stdout.

Usage

A simple Makefile is provided for convenience:

➜  rust-async git:(master) ✗ make help
async                          Runs non-blocking program
blocking                       Runs blocking program
help                           Prints help for targets with comments