Cargo Features

[dependencies]
async-channel = { version = "2.5.0", default-features = false, features = ["std", "portable-atomic"] }
default = std

The std feature is set by default whenever async-channel is added without default-features = false somewhere in the dependency tree.

std default

Enables std of concurrent-queue and event-listener-strategy

portable-atomic

Enables portable-atomic and portable-atomic-util, portable-atomic of concurrent-queue and event-listener-strategy

async-channel has 3 features without comments.