Cargo Features

async_io_stream has no features set by default.

[dependencies]
async_io_stream = { version = "0.3.3", features = ["map_pharos", "tokio_io"] }
map_pharos = pharos
tokio_io = tokio

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](https://rust-lang.github.io/rfcs/3491-remove-implicit-features.html).

pharos map_pharos?
tokio tokio_io?