Features from optional dependencies

futures-io implicit feature

Enables futures-io

futures-io:

The AsyncRead, AsyncWrite, AsyncSeek, and AsyncBufRead traits for the futures-rs library

terminal-io implicit feature

Enables terminal-io

terminal-io:

Utilities for reading and writing on terminals

tokio implicit feature

Enables tokio

tokio:

An event-driven, non-blocking I/O platform for writing asynchronous I/O backed applications