Cargo Features

containerd-client = { version = "0.5.0", default-features = false, features = ["connect", "docs"] }
connect default = tokio, tower

Affects containerd-client::connect

default = connect

Technically Tonic doesn't require Tokio and Tower dependencies here. However we need them to implement connect helper and it's highly unlikely that Tonic will be used with any other async runtime (see So we enable connect feature by default (use --no-default-features otherwise).

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.

tokio connect
tower connect