lazy-pregen-0.1.4 is not a library.
lazy-pregen 
A Rust command line Minecraft Server wrapper used to pregenerate chunks.
lazy-pregen was made for personal use and thus has several issues that the author did not care to deal with. It is highly recommended to read the above documentation link.
Usage
Run the following command:
cargo install lazy-pregen
and then, assuming your PATH variable is set up properly, run the pregenerator:
lazy-pregen [DIRECTORY]
If no directory is specified, it defaults to the current working directory.