Add this to Cargo.toml:
rust
[dependencies]
fcm = "0.6"
tokio = "0.1"
futures = "0.1"
then add this to your crate root:
rust
extern crate fcm;
extern crate tokio;
extern crate futures;
Check out the examples directory for a simple sender.
To see it used in a real project, take a look to the XORC Notifications, which is a full-fledged consumer for sending push notifications.