Cargo Features

[dependencies]
file-fastly = { version = "0.6.9", default-features = false, features = ["only-openssl", "native-tls", "rustls"] }
default = native-tls

The native-tls feature is set by default whenever file-fastly is added without default-features = false somewhere in the dependency tree.

only-openssl = native-tls, openssl
native-tls default only-openssl? = hyper-native-tls

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

hyper-native-tls native-tls
openssl only-openssl?
rustls implicit feature

Enables rustls ^0.20

rustls:

Rustls is a modern TLS library written in Rust