Visualizing an existing project with a flowgraph / pipeline graph / flowchart (GraphViz)

In the early stages of Rust learnings but diving into an existing project where I'm trying to visualize how each of the components in the project are working together. Rust nightly used to provide the following:

rustc +nightly -Zunpretty="flowgraph=main" src/main.rs

It doesn't appear to be an option anymore?

A similar utility that I've used before in Ruby is: https://github.com/zeisler/visualize_ruby

For those familiar with GStreamer, it provides pipeline graphs that can be generated: https://gstreamer.freedesktop.org/documentation/tutorials/basic/debugging-tools.html?gi-language=c#getting-pipeline-graphs

Appreciate the help in advance!