It's used only as a dev dependency in 6 crates.

Depender (with downloads and own rev deps) tokio-mock-task version
164K 82 tokio-timer dev ^0.1.0
124K 16 tokio-sync dev ^0.1.1
39K 4 tokio-buf dev ^0.1.1
tokio-os-timer dev ^0.1.0
async-lease dev ^0.1
async-option dev ^0.1