mmap is used at run time in 16 crates (of which 6 optionally, 8 directly). It's used only as a dev dependency in 1 crate.

Depender (with downloads and own rev deps) mmap version
900 4 perfcnt 0.1.*
110 x86test ^0.1.1
coroutine-rs *
1 cupi *
cylus ^0.1.1
1 driverkit 0.1.*
fit_no_io dev ^0.1.0
remarkable ^0.1.1
wfbuf ^0.1