Cargo Features

xz2 has no features set by default.

xz2 = { version = "0.1.7", features = ["tokio", "static"] }
tokio = futures, tokio-io

Enables static of lzma-sys

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-io tokio?
futures tokio?

Enables futures ^0.1.26