Cargo.toml producing mio error

Cargo.toml

[package]
name = "xdaytime"
version = "0.1.0"
edition = "2018"


[features]
default = ["os-poll", "os-ext", "net"]
os-poll = []
os-ext = ["os-poll"]
net = []

[dependencies]
mio = "0.7.9"

# Unfortunately the above Cargo.toml results in an error in my main.rs at
#   use mio::net::UdpSocket;
# The error is 
#   error[E0432]: unresolved import `mio::net`
#    --> src\main.rs:1:10
#    |
#  1 | use mio::net::UdpSocket;
#    |          ^^^ could not find `net` in `mio`
#