firefox/docs/rust-components/topic-guides/viaduct.md

Viaduct

Viaduct initialization is required for all platforms and for multiple components. The README explains the component in more detail.

Firefox Desktop, Firefox Android, and Firefox iOS all already initialize viaduct. You only need to take action if you want to use the Rust components on a new application.

There are 3 different options to use viaduct:

• Any libxul based can ignore initialization, since it's handled by libxul.
• Using the reqwest backend, which uses the reqwest library and a reqwest-managed thread.
• Implementing the C FFI like libxul does (https://searchfox.org/mozilla-central/source/toolkit/components/viaduct).